Phoenix Point

Popped this today so I take it must be fixed now although I suspect it's still a bit glitchy.

Update from the forums 21/11/2021 - it popped for a guy after he used a normal skill (use shoulder mounted Fury turret). So to be safe you need to use every normal ability of all soldiers.

In theory here's how it should work. There are 21 active skills that need to be used. Some of these skills are only unlocked as your soldiers level up through to level seven. Passive skills don't count.

A quick guide to the skills can be found here on the Phoenix Point Wiki:
http://wiki.phoenixpoint.com/Classes_and_Skills

The skills that count are as follows, by class:

Assault: Dash, Onslaught, Rapid Clearance (3)
Heavy: War Cry, Boom Blast, Rage Burst (3)
Sniper: Quick Aim, Marked for Death (2)
Technician: Manual Control, Field Medic, Electric Reinforcement (3)
Infiltrator: Deploy Decoy, Spider Drone Pack, Vanish (3)
Beserker: Armour Break, Adrenaline Rush (2)
Priest: Mind Control, Induce Panic, Mind Crush, Frenzy, Psychic Scream (5)

The priest one is tricky because the Frenzy and Psychic Scream are characteristic of the type of head mutation they have so you'll need Priests with the right head mutation.

You can apply your own mutations in the game also with mutation lab.

I'd done all skills lots of times and it never popped even with the latest update. It actually popped immediately after my infiltrator deployed a single spider drone, not the spider drone pack. The single is a default ability, and not one of those unlocked later. So it backs up the theory that it needs every ability to be used, not just the 21 special skills.

So my advice is, if it doesn't unlock after trying out all the 21 active ones above, try on the others also like the technicians various mech arms stuff (remove mindfragger, healing, repair etc etc).

Good Luck, message me if there are any questions or you're having issues and I will share what more I know.