diff --git a/comicapi/comet.py b/comicapi/comet.py
index 12596df..d3afe3f 100644
--- a/comicapi/comet.py
+++ b/comicapi/comet.py
@@ -165,12 +165,12 @@ class CoMet:
         # loop for genre tags
         for n in root:
             if n.tag == "genre":
-                md.genres.append((n.text or "").strip())
+                md.genres.add((n.text or "").strip())
 
         # loop for character tags
         for n in root:
             if n.tag == "character":
-                md.characters.append((n.text or "").strip())
+                md.characters.add((n.text or "").strip())
 
         # Now extract the credit info
         for n in root:
diff --git a/comicapi/comicbookinfo.py b/comicapi/comicbookinfo.py
index 369d731..2a636de 100644
--- a/comicapi/comicbookinfo.py
+++ b/comicapi/comicbookinfo.py
@@ -89,7 +89,7 @@ class ComicBookInfo:
         metadata.year = utils.xlate_int(cbi["publicationYear"])
         metadata.issue_count = utils.xlate_int(cbi["numberOfIssues"])
         metadata.description = utils.xlate(cbi["comments"])
-        metadata.genres = utils.split(cbi["genre"], ",")
+        metadata.genres = set(utils.split(cbi["genre"], ","))
         metadata.volume = utils.xlate_int(cbi["volume"])
         metadata.volume_count = utils.xlate_int(cbi["numberOfVolumes"])
         metadata.language = utils.xlate(cbi["language"])
diff --git a/comicapi/comicinfoxml.py b/comicapi/comicinfoxml.py
index d45cb6e..7c62ebf 100644
--- a/comicapi/comicinfoxml.py
+++ b/comicapi/comicinfoxml.py
@@ -73,7 +73,7 @@ class ComicInfoXml:
                 text = ""
                 if isinstance(md_entry, str):
                     text = md_entry
-                elif isinstance(md_entry, list):
+                elif isinstance(md_entry, (list, set)):
                     text = ",".join(md_entry)
                 else:
                     text = str(md_entry)
@@ -208,14 +208,14 @@ class ComicInfoXml:
         md.day = utils.xlate_int(get("Day"))
         md.publisher = utils.xlate(get("Publisher"))
         md.imprint = utils.xlate(get("Imprint"))
-        md.genres = utils.split(get("Genre"), ",")
+        md.genres = set(utils.split(get("Genre"), ","))
         md.web_link = utils.xlate(get("Web"))
         md.language = utils.xlate(get("LanguageISO"))
         md.format = utils.xlate(get("Format"))
         md.manga = utils.xlate(get("Manga"))
-        md.characters = utils.split(get("Characters"), ",")
-        md.teams = utils.split(get("Teams"), ",")
-        md.locations = utils.split(get("Locations"), ",")
+        md.characters = set(utils.split(get("Characters"), ","))
+        md.teams = set(utils.split(get("Teams"), ","))
+        md.locations = set(utils.split(get("Locations"), ","))
         md.page_count = utils.xlate_int(get("PageCount"))
         md.scan_info = utils.xlate(get("ScanInformation"))
         md.story_arcs = utils.split(get("StoryArc"), ",")
diff --git a/comicapi/genericmetadata.py b/comicapi/genericmetadata.py
index a22a5f6..981d5f4 100644
--- a/comicapi/genericmetadata.py
+++ b/comicapi/genericmetadata.py
@@ -72,7 +72,7 @@ class Credit(TypedDict):
 class ComicSeries:
     id: str
     name: str
-    aliases: list[str]
+    aliases: set[str]
     count_of_issues: int | None
     count_of_volumes: int | None
     description: str
@@ -107,17 +107,17 @@ class GenericMetadata:
     series_id: str | None = None
 
     series: str | None = None
-    series_aliases: list[str] = dataclasses.field(default_factory=list)
+    series_aliases: set[str] = dataclasses.field(default_factory=set)
     issue: str | None = None
     title: str | None = None
-    title_aliases: list[str] = dataclasses.field(default_factory=list)
+    title_aliases: set[str] = dataclasses.field(default_factory=set)
     publisher: str | None = None
     month: int | None = None
     year: int | None = None
     day: int | None = None
     issue_count: int | None = None
     volume: int | None = None
-    genres: list[str] = dataclasses.field(default_factory=list)
+    genres: set[str] = dataclasses.field(default_factory=set)
     language: str | None = None  # 2 letter iso code
     description: str | None = None  # use same way as Summary in CIX
 
@@ -141,9 +141,9 @@ class GenericMetadata:
     series_groups: list[str] = dataclasses.field(default_factory=list)
     scan_info: str | None = None
 
-    characters: list[str] = dataclasses.field(default_factory=list)
-    teams: list[str] = dataclasses.field(default_factory=list)
-    locations: list[str] = dataclasses.field(default_factory=list)
+    characters: set[str] = dataclasses.field(default_factory=set)
+    teams: set[str] = dataclasses.field(default_factory=set)
+    locations: set[str] = dataclasses.field(default_factory=set)
 
     alternate_images: list[str] = dataclasses.field(default_factory=list)
     credits: list[Credit] = dataclasses.field(default_factory=list)
@@ -183,7 +183,7 @@ class GenericMetadata:
             if new is not None:
                 if isinstance(new, str) and len(new) == 0:
                     setattr(self, cur, None)
-                elif isinstance(new, list) and len(new) == 0:
+                elif isinstance(new, (list, set)) and len(new) == 0:
                     pass
                 else:
                     setattr(self, cur, new)
@@ -332,7 +332,7 @@ class GenericMetadata:
         add_attr_string("day")
         add_attr_string("volume")
         add_attr_string("volume_count")
-        add_attr_string("genres")
+        add_string("genres", ", ".join(self.genres))
         add_attr_string("language")
         add_attr_string("country")
         add_attr_string("critical_rating")
@@ -356,9 +356,9 @@ class GenericMetadata:
         add_attr_string("story_arcs")
         add_attr_string("series_groups")
         add_attr_string("scan_info")
-        add_attr_string("characters")
-        add_attr_string("teams")
-        add_attr_string("locations")
+        add_string("characters", ", ".join(self.characters))
+        add_string("teams", ", ".join(self.teams))
+        add_string("locations", ", ".join(self.locations))
         add_attr_string("description")
         add_attr_string("notes")
 
@@ -417,7 +417,7 @@ md_test: GenericMetadata = GenericMetadata(
     day=1,
     issue_count=6,
     volume=1,
-    genres=["Sci-Fi"],
+    genres={"Sci-Fi"},
     language="en",
     description=(
         "For 12-year-old Anda, getting paid real money to kill the characters of players who were cheating"
@@ -441,9 +441,9 @@ md_test: GenericMetadata = GenericMetadata(
     story_arcs=["Here and Now"],
     series_groups=["Futuristic Tales"],
     scan_info="(CC BY-NC-SA 3.0)",
-    characters=["Anda"],
-    teams=["Fahrenheit"],
-    locations=utils.split("lonely  cottage ", ","),
+    characters={"Anda"},
+    teams={"Fahrenheit"},
+    locations=set(utils.split("lonely  cottage ", ",")),
     credits=[
         Credit(primary=False, person="Dara Naraghi", role="Writer"),
         Credit(primary=False, person="Esteve Polls", role="Penciller"),
diff --git a/comictaggerlib/taggerwindow.py b/comictaggerlib/taggerwindow.py
index bf632c9..61a17d2 100644
--- a/comictaggerlib/taggerwindow.py
+++ b/comictaggerlib/taggerwindow.py
@@ -917,7 +917,7 @@ class TaggerWindow(QtWidgets.QMainWindow):
         md.series = utils.xlate(self.leSeries.text())
         md.title = utils.xlate(self.leTitle.text())
         md.publisher = utils.xlate(self.lePublisher.text())
-        md.genres = utils.split(self.leGenre.text(), ",")
+        md.genres = set(utils.split(self.leGenre.text(), ","))
         md.imprint = utils.xlate(self.leImprint.text())
         md.description = utils.xlate(self.teComments.toPlainText())
         md.notes = utils.xlate(self.teNotes.toPlainText())
@@ -932,9 +932,9 @@ class TaggerWindow(QtWidgets.QMainWindow):
         md.series_groups = utils.split(self.leSeriesGroup.text(), ",")
         md.alternate_series = self.leAltSeries.text()
         md.web_link = utils.xlate(self.leWebLink.text())
-        md.characters = utils.split(self.teCharacters.toPlainText(), "\n")
-        md.teams = utils.split(self.teTeams.toPlainText(), "\n")
-        md.locations = utils.split(self.teLocations.toPlainText(), "\n")
+        md.characters = set(utils.split(self.teCharacters.toPlainText(), "\n"))
+        md.teams = set(utils.split(self.teTeams.toPlainText(), "\n"))
+        md.locations = set(utils.split(self.teLocations.toPlainText(), "\n"))
 
         md.format = utils.xlate(self.cbFormat.currentText())
         md.country = utils.xlate(self.cbCountry.currentText())
diff --git a/comictalker/talkers/comicvine.py b/comictalker/talkers/comicvine.py
index f294855..43ef298 100644
--- a/comictalker/talkers/comicvine.py
+++ b/comictalker/talkers/comicvine.py
@@ -480,8 +480,8 @@ class ComicVineTalker(ComicTalker):
         aliases = record.get("aliases") or ""
 
         return ComicSeries(
-            aliases=utils.split(aliases, "\n"),
-            count_of_issues=record.get("count_of_issues", 0),
+            aliases=set(utils.split(aliases, "\n")),
+            count_of_issues=record.get("count_of_issues"),
             count_of_volumes=None,
             description=record.get("description", ""),
             id=str(record["id"]),
@@ -630,7 +630,7 @@ class ComicVineTalker(ComicTalker):
             tag_origin=TagOrigin(self.id, self.name),
             issue_id=utils.xlate(issue.get("id")),
             series_id=series.id,
-            title_aliases=utils.split(issue.get("aliases"), "\n"),
+            title_aliases=set(utils.split(issue.get("aliases"), "\n")),
             publisher=utils.xlate(series.publisher),
             description=issue.get("description"),
             issue=utils.xlate(IssueString(issue.get("issue_number")).as_string()),
@@ -647,23 +647,18 @@ class ComicVineTalker(ComicTalker):
         else:
             md.cover_image = issue.get("image", {}).get("super_url", "")
 
-        md.alternate_images = []
         for alt in issue.get("associated_images", []):
             md.alternate_images.append(alt["original_url"])
 
-        md.characters = []
-        for character in issue.get("character_credits", []):
-            md.characters.append(character["name"])
+        for character in issue.get("character_credits", set()):
+            md.characters.add(character["name"])
 
-        md.locations = []
-        for location in issue.get("location_credits", []):
-            md.locations.append(location["name"])
+        for location in issue.get("location_credits", set()):
+            md.locations.add(location["name"])
 
-        md.teams = []
-        for team in issue.get("team_credits", []):
-            md.teams.append(team["name"])
+        for team in issue.get("team_credits", set()):
+            md.teams.add(team["name"])
 
-        md.story_arcs = []
         for arc in issue.get("story_arc_credits", []):
             md.story_arcs.append(arc["name"])
 
diff --git a/testing/comicvine.py b/testing/comicvine.py
index 239ce7d..9db59b5 100644
--- a/testing/comicvine.py
+++ b/testing/comicvine.py
@@ -159,7 +159,7 @@ cv_not_found = {
 comic_series_result = comicapi.genericmetadata.ComicSeries(
     id=str(cv_issue_result["results"]["volume"]["id"]),
     name=cv_issue_result["results"]["volume"]["name"],
-    aliases=[],
+    aliases=set(),
     count_of_issues=cv_volume_result["results"]["count_of_issues"],
     count_of_volumes=None,
     description=cv_volume_result["results"]["description"],
@@ -172,7 +172,7 @@ comic_series_result = comicapi.genericmetadata.ComicSeries(
 date = utils.parse_date_str(cv_issue_result["results"]["cover_date"])
 comic_issue_result = comicapi.genericmetadata.GenericMetadata(
     tag_origin=comicapi.genericmetadata.TagOrigin("comicvine", "Comic Vine"),
-    title_aliases=cv_issue_result["results"]["aliases"] or [],
+    title_aliases=set(),
     month=date[1],
     year=date[2],
     day=date[0],
@@ -203,7 +203,7 @@ cv_md = comicapi.genericmetadata.GenericMetadata(
     day=date[0],
     issue_count=cv_volume_result["results"]["count_of_issues"],
     volume=None,
-    genres=[],
+    genres=set(),
     language=None,
     description=cv_issue_result["results"]["description"],
     volume_count=None,
@@ -223,9 +223,9 @@ cv_md = comicapi.genericmetadata.GenericMetadata(
     story_arcs=[],
     series_groups=[],
     scan_info=None,
-    characters=[],
-    teams=[],
-    locations=[],
+    characters=set(),
+    teams=set(),
+    locations=set(),
     credits=[
         comicapi.genericmetadata.Credit(person=x["name"], role=x["role"].title(), primary=False)
         for x in cv_issue_result["results"]["person_credits"]
diff --git a/tests/comicarchive_test.py b/tests/comicarchive_test.py
index d688b23..ecedc04 100644
--- a/tests/comicarchive_test.py
+++ b/tests/comicarchive_test.py
@@ -98,9 +98,9 @@ def test_save_cbi_rar(tmp_path, md_saved):
         story_arcs=[],
         series_groups=[],
         scan_info=None,
-        characters=[],
-        teams=[],
-        locations=[],
+        characters=set(),
+        teams=set(),
+        locations=set(),
     )
 
 
diff --git a/tests/metadata_test.py b/tests/metadata_test.py
index 79a84ab..364bc99 100644
--- a/tests/metadata_test.py
+++ b/tests/metadata_test.py
@@ -23,9 +23,9 @@ def test_cbi(md_saved):
         story_arcs=[],
         series_groups=[],
         scan_info=None,
-        characters=[],
-        teams=[],
-        locations=[],
+        characters=set(),
+        teams=set(),
+        locations=set(),
         pages=[],
         alternate_series=None,
         alternate_number=None,
@@ -48,8 +48,8 @@ def test_comet(md_saved):
         story_arcs=[],
         series_groups=[],
         scan_info=None,
-        teams=[],
-        locations=[],
+        teams=set(),
+        locations=set(),
         pages=[],
         alternate_series=None,
         alternate_number=None,