The mystical powers of the earth and sea meet in an unshakable alliance between Elves and Merfolk. The real heavy-hitters of this deck are Elvish Archdruid and Merfolk Sovereign, with a bit of help from Coralhelm Commander. But the kicker behind them all is Xenograft, which when you get them out makes all your creatures Elf/Merfolk hybrids, and able to attain all the power of the three commanding creatures. Speaking of, let's examine what they do, shall we?
Elvish Archdruid is both a deadly mana-ramp card, and a power-up for your other elf creatures. It allows you to add a green mana to your mana-pool for each elf under your control, while giving them each +1/+1. While not excessively deadly on its own, put a few together and you can potentially give your creatures a +4/+4 boost.
Merfolk Sovereign is essentially the Merfolk version of Elvish Archdruid, powering up all your merfolk in a similar fashion, but unlike the elf, you can tap it to make a merfolk under your control unblockable for the turn, allowing you to deal devastating damage that adds up.
Coralhelm Commander is an ally to all Merfolk as well. A leveler, it costs only two blue mana to cast, and levels up for one colorless mana. With the mana-ramping ability of the elves, you can reach lvl 4 relatively easily, turning this 2/2 creature into a 4/4 with flying, that also gives all your other merfolk an additional +1/+1.
Xenograft can make your creatures any type in addition to any other types they already are. Drop one and make all your merfolk creatures Elves, adding more mana for Elvish Archdruid while also pumping them up even further. Drop another and make your Elves into Merfolk and you can potentially drop a 13/13, potentially unblockable Llanowar Elves for a single green mana.
And once these cards are all pumped for the fight, send in Prime Speaker Zegana who not only will be empowered from the abilities of your other cards, but from her own ability as well, entering the battlefield with +1/+1 counters equal to the highest power among creatures you control. If your creatures aren't big enough, a
Biomass Mutation
can quickly change that.
