Its ability to sacrifice creatures synergizes perfectly with token-heavy strategies, allowing you to churn through your deck while feeding into graveyard or sacrifice-based mechanics
Umbra armor has no effect if the enchanted creature is put into a graveyard for any other reason, such as if it's sacrificed, if the "legend rule" applies to it, or if its toughness is 0 or less
Two Zombie tokens, even entering tapped, is a huge addition to the board
Non-combat related ways to dish out poison counters are also important for any infect strategy and Reaper of Sheoldred, Vraska's Fall, Bloodroot Apothecary, and Venerated Rotpriest do some dirty work
The fifth chapter "Ultimate End" buffs your entire team and gives them all indestructible counters
She also works outside of Elf or Token decks, which makes her the most versatile