As the title says, I'm going to ask you something:
Picture that you have a brand new OC. This OC is an Immortal alien war god who carries a living Greatsword with ease, and whose sole purpose in life is to fight, kill, take over and destroy things.
This OC was also trapped inside his weapon ages ago, when him and his entire race were defeated after rebeling those who wanted to control them.
His race is also like him, powerful, ancient and proud.
Now picture him loose from his prison, ready to unleash havoc and mayhem where ever he goes, ready to get revenge for his brothers and sisters and letting the world know that he has returned to destroy them for what they did to him.
Now you need to put on this OC the Vibes of the voicelines of old Aatrox and new Aatrox.
Wouldn't you agree that giving this OC a "narcissistic, meglomaniac, proud, bloodthirsty , rageful, Megatron like" voice is a better choice then giving him a "Behind the scene, puppetmaster in the shadows, schemeing mastermind" kind of voice?
Think about that.