just curious, what highest star vader can be made from achievememts

Scorpion1980

hi all
im just curious if anyone can confirm, what is the highest star vader possible from achievements? when you unlock him is he 4* and the his current max is?

Kr4itok_

I've heard you can take him up to 5* from achievements, but thats just what I read here on the forums. I know you can get his shards from GW completions as well.