Odin (Marvel)
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Old Lace (Marvel)
Omega Flight (Marvel)
Omega Red (Marvel)
Omega Sentinel (Marvel)
Omega the Unknown (Marvel)
Onslaught (Marvel)
Oracle (Marvel)
Ord (Marvel)
Orphan (Marvel)
Orphan-Maker (Marvel)
Outlaw Kid (Marvel)
Overlord (Marvel)
Owl (Marvel)
Ozymandias (Marvel)
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