how did he gain his freedom?

Freezing and shattering his captors to bits

why doesn't he use more modern weaponry from hunting down the Omarasa?

I mean it's made of magic crystals but the gun still shoots A laser, it does the job

Could consider partially a staff for it's nature

The inside of the barrel is chained with a long line of fire infused magic gems, lined up makes it so they're focused and more powerful, and that fire becomes sort of ultra focused into a beam
The trigger pounds an electricity gem into the first fire gem of this line, serving as activation to shoot the laser.

Though these electric gems run out when not I'm the Guilliguine home planet Slonicha, when he's too far the planets spirit is disconnected from the gem

So he either has to return to his planet, or Alternatively, pray to his gun to to restore the power of his home to it, which is a lot funnier and much easier

Blessed be the firearm

it would still make more sense to retrofit a more precise weapon rather than some weaponry scrap, lasers need really precise optics to work well, much more than bullets

It's fictional magic crystals I didn't put a lot of thought of real life logistics and function into it

then it would make sense to use different wording than laser to not draw parallels between real life

Ooh interesting!

Thank!