First strike (This creature deals combat damage before creatures without first strike.)
Reach (This creature can block creatures with flying.)
At the beginning of combat on your turn, put X +1/+1 counters on another target creature you control, where X is Halana and Alena's power. That creature gains haste until end of turn.
Halana and Alena snowball a single creature into a game-ending threat every combat by dumping +1/+1 counters equal to their power and granting haste. Play ramp, drop a fat or evasive creature, then turn it into a one-shot kill the next combat. As Halana and Alena grow (via counter doublers or their own counters), the payload only gets bigger.
Free, repeatable +1/+1 counter pile every turn with haste so freshly-cast creatures attack immediately
Built-in evasion potential and counter synergies that scale into one-shot commander-damage kills
Naturally aggressive GR shell that closes games fast and pressures the table
Pairs explosively with trample, double strike, and counter doublers
Highly creature-dependent; sweepers and spot removal set you back hard
The counter target is single and telegraphed, inviting removal in response to combat trigger
Limited interaction in GR—weak to control, stax, and flyers you can't profitably block
Removing or chump-blocking the buffed creature can blank a whole turn