Right.. well, Sephiroth and Kefka are the more obvious ones.. there's also Ultemecia and Kuja
Gaia in Grandia can infect whole cities and turn them into stone and stuff... practically killing off the world
Sin is an interesting one too, he destroys whole cities effortlessly and can warp space n stuff
There's also 'Meta-God' in shadow hearts, who could probably destroy worlds... seraphic radiance would beat him though
Would the Metal Gears count? I mean, they're capable of dangerous things... nuclear things.. they get owned by snake though
And why is Kain invincible? Raziel is invincible, cause he can't die. His soul is also the key to rewrite history and alter the time continium.. I'm sure that counts for something
Mettool Helmet, you get nothing but *tink, tink*. Freakin' Invinsible
Tom Nook, he said...he said I owe him 50 Billion bells and had to pay it in two days. I said NO! I...I woke up and little Timmy's head was in my bed. I went to the store and Timmy was there and he was going on like nothing ever happened. Not only that, but K.K. Slider had an "accedent" and won't come to town anymore.
Deathstar - any Star wars game
The manhacks - HL2 (they can be real pains)
an halo - halo
the helghast - Killzone
the flood - halo
those really really really big giants - Painkiller
heaven's hitman - Painkiller
the pile of hay who says "buff you, *******!" - Conker's bad fur day and Live & reloaded
Arsenal gear - Metal gear solid 2
Me with a battlecruiser army and Sajuuk - Homeworld 2
The aliens - Metal slug series
"the three brothers" - Diablo 2
the guy who follows you (the one who never dies and is carrying a gun) - Silent hill 4
"it" - Resident evil 4
Anubis and Aumaan - Zone of the enders : 2:nd runner
Giygas - Earthbound
the colussuses - Shadow of the colossus
... - ...
Cant think of any more 🙁