Chaurus Breeding Pit is April 2017 monthly reward. As always, you should have to reach rank nine (Mage) in Versus Battle by the end of this month to get one copy of this card, rank five (Warrior) to earn a second copy of it and rank one (Thief) to get the third one.
Chaurus Breeding Pit is the new unique Agility Action. It costs 10 magicka. You will summon a Chaurus Reaper in each lane after playing this Action. As you can see Chaurus Breeding Pit is a little AOE that gives all enemy creatures -1/-1 in each lane and also give you two creatures with stats 5-4 on the board.
Chaurus Reaper costs 7 magicka so two copies of it should cost 14 magicka. Chaurus Breeding Pit has some value because it costs 10 magicka. But we do not play Chaurus Reaper in ranked mode because it is very slow. The new Action is slow too even for control decks. We have the legendary Action Nest of Vipers that fills the lane with Territorial Vipers. So this card can give us 4 creatures with 1-1 stats and keywords Lethal and Charge. It costs 10 magicka too but we do not see this potential removal in ranked mode. That is why we think that Chaurus Breeding Pit is slow too and we will not see this card in ranked mode in control decks. But maybe people will try to play one copy of it in Control Monk. And of course this new Agility Action is not a card for midrange or aggressive decks.
We can play Chaurus Breeding Pit on Arena for late game because of AOE effect and stats 10-8 for 10 magicka. But it will not be the best unique pick on Arena.