Kilroy the Eternal is a cosmic entity and the 1st God of the Bignoseverse. He is contained in a portal in said Verse. This portal leads to Kilroy's domain. The domain is also the home of the Infinose.
Kilroy has a good amount of fame on Earth, appearing in the Kilroy was here meme, which was started during World War II. The humans of Earth are not aware of the true significance of Kilroy.
Kilroy the Eternal is what appears to be a man with a prominent nose peeking over a wall and clutching it with his hands. The appearance of Kilroy's lower body is unknown.
Kilroy the Eternal's purpose is to defend and maintain the Infinose, an important artifact within the Bignoseverse. If this artifact were to be destroyed, the noses of everyone would be vaporized into nothingness. As noses are the main source of power and weapon in combat in the Bignoseverse, the destruction of the Infinose would be devastating.
Kilroy is capable of elongating his own nose to increase his power. This is useful when the Infinose is under attack. Kilroy can use his nose to hit attackers. He can also use his fists to crush them.
Kilroy's strongest attack is the ability to start multiplying at an insane rate (something that has little to do with said phrase). He is able to preform thousands of attacks at once.
In an emergency situation, Kilroy can warp the Infinose and himself away by uttering the phrase "Kilroy was here".