Immortalist

A sentient conscience that has immense power and utilizes that power to prolonge oneself.

Thanos was an Immortalist.

Nazi

A person who does not agree with one's opinions, usually used out of context or where the word does not apply.

"Punch a Nazi"

Dog

A domesticated animal that is usually referred to as man's best friend, known also as a pet better than cats.

'Hey, Jimmy I got a new cat.'
'Whaaaaaaaaaaaaaaaaaaaaaaaaaaaaat, you should have gotten a Dog!'