Gorm must be blocked if able, and Gorm must be blocked by two or more creatures if able.
Gorm is a forced-block engine: opponents must gang-block him with two or more creatures, so you punish them with deathtouch, trample, or massive pumps to blow out their board in combat. Paired with his canonical partner Virtus the Veiled, you instead want him unblockable-adjacent or just swing Virtus to halve life totals, but on his own Gorm anchors a green stompy/combat-trick deck that turns every attack into a one-sided trade or a board-wipe with the right enabler.
Forces multi-creature blocks, letting deathtouch or trample punish opponents brutally
Vigilance keeps him back on defense while still attacking
Partner gives instant access to Virtus for a half-life-loss threat
Cheap (4 MV) green body that fits early curves
Helpless against removal, edicts, and bounce since the whole plan hinges on him being on board
Forced-block ability does nothing against fliers, deathtouch tokens, or no-block decks like control/combo
Color identity is mono-green (or G/B with Virtus), so card pool and interaction are thin
Telegraphed combat plan that smart opponents simply chump or refuse to attack into
Recurring trample turns gang-blocks into excess damage to the face.
Lean hard into deathtouch granters (Basilisk Collar, Bow of Nylea, Gorgon's Head) and trample sources so forced blocks are pure profit, and add protection like Heroic Intervention and Snakeskin Veil to keep him alive. Run Virtus as partner to splash black tutors and removal, plus reanimation if you want a backup threat. Push the power level with ramp (Sol Ring, Three Visits) and evasive finishers so you aren't reliant on a single fragile attacker.