Mermails are a somewhat competent offensive combo deck within the N/R format, due to being able to swarm while having the ability to recover when blown out.
By abusing Mermail Abysslinde to obtain and maintain board
presence than using the Mermail Abyssnerei (as a water Honest), Abyss equips and other boost spells to push for game. If its necessary to buy time getting 2 Mermail Abbysslungs out (what isn't hard to do) creates a attack lock until one of them is removed.