Creatures you control that are enchanted or equipped have double strike.
At the beginning of each combat, you may attach target Aura or Equipment attached to a creature you control to target creature you control.
Equipped creature gets +2/+0 and has vigilance.
Whenever equipped creature dies, return it to its owner's hand.
Equip
Halvar is a mono-white Voltron commander: suit up one creature (often Halvar himself or another evasive threat) with Auras and Equipment to grant double strike, then swing for lethal commander damage. Each combat you freely move your buffs onto the best attacker, and Sword of the Realms protects equipped creatures by bouncing them to hand when they die. You ramp into a few key pieces of equipment, then close fast before opponents stabilize.
Double strike on enchanted/equipped creatures doubles all your combat buffs and on-hit triggers
Free combat-step reattachment lets you redirect Auras/Equipment to dodge removal or chase the best target
Sword of the Realms turns 'dies' into a bounce, blanking spot removal on your equipped creature
Mono-white means consistent mana and access to strong protection and equipment tutors
Classic single-threat Voltron vulnerability: edicts, exile, and -X/-X bypass the bounce protection
Mono-white struggles with raw card advantage and ramp compared to other colors
Board wipes and fogs can stall the all-in combat plan
Slow to set up if you draw equipment without creatures or vice versa
Sword of the Realms
Halvar's back half gives vigilance, +2/+0, and a death-to-hand bounce that makes your carrier nearly impossible to kill with targeted removal.