A little thing about his power.

1. He can't imagine himself becoming something he isn't. (Like a god, dog, ogre, pig, etc.)

2. If he's battling someone he can't imagine himself winning to make it happen. (Example: "I'm losing this battle, I'll just imagine myself winning." -doesn't work like that)

3. It consumes no mana to use this ability, but instead, it takes willpower. If the MC has his will broken then he won't be able to imagine anything into existence for the time being.

4. I know guns would be funny and cool, where's the fun in that? It would be a cool gag but it would completely ruin everything, so no, the MC won't be imagining guns into the world. (sorry, not sorry.)