How to get better pirates to add to your crew and can you evolve or merge pirates?

You can get pirates from cages or crewchests, as a reward from skirmiches and sometimes you find one when opening fog.

Cages you get from the traders and sometimes from island fights.

You can get a free crewchest daily from the store.

You can level up crewmen by fusing them. If you dont have the machine yet, just increase your pirate lvl. You can not gain extra stars from fusing.