Jujutsu Kaisen vs Ben 10

Connection:

Both are ancient, pure evil supernatural overlords whose minds still reside in small parts of themselves (Sukuna's mind in his fingers and Zs'Skayr's in his DNA) that would fall in the hands of the young heroic protagonists (Yuji Itadori and Ben Tennyson respectively), allowing them to take root in their subconscious. Protagonists would try to use these powers for good, but they would still exist, malevolent as ever as their connection to MC allowed them to take over them temporarily at moments. Showing highly sadistic personalities and often see others as mere worthless obstacles

Eventually, the heroes turns out to not be enough to hold them as they separate themselves from them, wreaking havoc in new bodies stronger than ever (Sukuna taking over Megumi Fushiguro and Zs'Skayr escaping Omnitrix), which includes both going into their "true" contorted forms much more horrifying than when the hero was using their power, becoming so powerful that previously-threatening enemies are practically nothing to them. Both are made even more dangerous by the fact that they are not only strong but intelligent, having a cunning mind and incredibly manipulative tendencies.

Both also have a group of beings similar to them that revived them (Other powerful Cursed Spirits reviving Sukuna and other aliens from Zs'Skayr's part of space reviving him) and both seem to have a special case with the protagonists as they really, REALLY like mentally torturing them