"Yomi" (黄泉 Yomi), referred to as "Abyss" in the official English sub (but unrelated to the "Abyss-" archetype), is an archetype used by the Familiar of Red Nova in Yu-Gi-Oh! 5D's. "Treeborn Frog" belong to this archetype.
The regular "Yomi" monsters are small fiendish creatures wearing hooded cloaks. Each of them holds a different item, based on their "post".
"Yomi" (黄泉) translates to "underworld". The archetype's name can also be a pun on "Yomigaeru" (よみがえる), meaning "Resurrection".
The regular "Yomi" monsters consist of locking the opponent's attacks by constantly Special Summoning and destroying themselves, inflicting damage to the opponent each time they do so. Once the player has gathered enough "Yomi" monsters in the Graveyard, their ace monster, "Abyss Ruler Mictlancoatl", can be Summoned. It ignores the lockdown and focuses solely on a straightforward offensive strategy; even though it only inflicts 600 damage as opposed to the other "Yomi" monsters' 800, its can destroy the opponent's cards instead of the player's own, and posseses massive ATK and DEF.