Each other creature you control enters with a number of additional +1/+1 counters on it equal to Arwen's toughness.
Cast cheap Arwen early, then flood the board with creatures that all arrive massively buffed with +1/+1 counters equal to her toughness. Pump her toughness to scale the buffs higher, and convert that counter advantage into overwhelming combat damage or counter-synergy payoffs. You win by going wide with oversized creatures and trampling/swinging through.
Free, scalable +1/+1 counters on every creature you play with no extra mana investment
Cheap 3-mana commander that comes down early and snowballs fast
Mono-green gives access to the best ramp, fight spells, and counter payoffs
Synergizes with token makers and flicker effects to multiply counter value
Heavily commander-dependent; removing Arwen shuts off the counter engine
Mono-green lacks interaction, card draw selection, and protection compared to multicolor
Toughness pumps are needed to scale, adding fragility and build-around tension
Board wipes are devastating since the deck overcommits to the battlefield
Legendary Creature — Elf Noble
