Njall Stormcaller

While Njall Stormcaller is not the most powerful psyker in the Imperium (which would be Mephiston), he is certainly one of the most potent psykers in the game based on what he brings to the table.

For starters, he has a 2+ armor save, and is one of the few special characters that can take upgrades. In Njall's case, that is Runic Terminator armor for a 2+4++ Invulnerable save.

Then as Mastery Level 2 Psyker, He gets to use two psychic powers a turn. He knows all Space Wolf codex powers, like Jaws of the World Wolf, but can instead trade those in for 2 powers from the basic rule book, including access to Divination and Biomancy.

On top of that, he has weird storm powers that in later turns of the game can result in lightning strikes!!!

What really makes him stand out though is the 24 inch anti psyker bubble that surrounds him due to his Runic Staff, and unlike regular Rune Priests his nullifies psychic powers on a 3+. Unlike the Psychic Hood which these items mimicked in 5th edition, these work against ALL psychic powers including activating force weapons, and blessings targeting enemy units!!

The only other race that can even come close for anti psyker is the Eldar with their runes of warding.

Here is my friends Njall Stormcaller that I painted for him.