Most of these are on the wiki. Check out the evolved movesets and decide which will support your strategy best.
Not everything is on there so that’s the idea of this thread. And people have different opinions and strategies so…
Which to evolve first: dreadghoul, cyberwyrm or dolphlare?
Dreadghoul no braniner - then cyberwrym then dolphare (i’ve found this to be the worst legendary…)
Of those I would choose cyberwyrm but not sure what kind of team do you run, because if you use a team focused on sleep the poison of cyberwyrm (passive) would ruin your strategy
Dreadghoul (he is Soulstealer right?) : Sleep focus team
Cyberwyrm: Stun or poison team strategy
Dolphare: Team with sacrifice summon strategy
My team use an stun/poison strategy so that is why I would go with Cyberwyrm
Trust me to get the worst legendary
Thanks to both of you for the tips!