Whenever you activate an ability that isn't a mana ability, if life was paid to activate it, you may pay that much life again. If you do, copy that ability. You may choose new targets for the copy.
Verrak doubles any non-mana activated ability that costs life, so you build a deck of life-paying activated abilities and copy them for double value. Early turns set up mana rocks and a few life-payment engines, then you leverage abilities like Razaketh tutors, Bolas's Citadel, or sacrifice/drain outlets twice each. You grind the table down while your lifelink commander and constant lifegain keep your life total fueling the engine.
Doubles powerful activated abilities (tutors, drains, mill, removal) for huge value per activation
Lifelink plus white/black lifegain refills the life you spend, making the engine sustainable
Flying deathtouch body is a real evasive threat and defensive deterrent
Cheap three-mana commander that comes down early and impacts the board immediately
Black/white access to the best tutors and recursion to assemble combos
The deck is heavily dependent on activated abilities that specifically pay life; off-theme cards do nothing for the engine
Constant life payment makes you vulnerable to aggro, burn, and life-loss punishers like Sanguine Bond against yourself
No card advantage on the commander itself beyond what abilities provide
Drain payoff that turns your aristocrats and copies into life swings.
Lean into the most efficient life-paying activated abilities and combo finishers—add fast mana (Mana Crypt, Jeweled Lotus), premium tutors (Vampiric Tutor, Demonic Tutor), and a tight Aetherflux Reservoir or infinite-life loop. Cut durdly value cards for redundant lifegain and ability-protection like Heroic Intervention and Boseiju. Tighten the curve so you can deploy Verrak and an engine piece on the same turn and protect against activated-ability hate.