Ajani Vengeant is the younger, wilder version of Ajani Goldmane. Ajani Vengeant costs four mana to cast, with at least one red and one white mana used. He enters the battlefield with three loyalty counters and has three abilities.
Ajani’s first ability is more white than red. Add one loyalty counter and tap a permanent, which doesn’t untap in it’s controller’s next untap phase. Did I say white? Perhaps I meant blue. Regardless, for a red/white planeswalker this is a useful ability, allowing you to remove a key blocker, or deny mana to an opponent with only a single mana source, or tie down the player to your right’s key attacker.
The second ability costs two loyalty counters and casts Lightning Helix for you. Always a useful spell to have, with the ability to strike at your choice of the four players around you. In multiplayer the life gain becomes useful too. There is a lot to be said for the simple tactic of alternating between this and Ajani Vengeant’s first ability.
Ajani Vengeant’s final ability costs seven loyalty counter and destroys all lands target player controls. In Grand Melee this can cripple a player when used a the right time. If timed poorly, the player will have a chance to recover and wreak revenge. Also for Grand Melee is the consideration that in using this ability you are effectively gifting a point to another player at the table rather than taking it for yourself. There are no rewards for doing that! This ability is best used carefully, if at all.
Verdict: Marginal. A deck based around Ajani Vengeant is unlikely to do well, but the card can be used to strengthen certain other decks. In Ajani Vengeant’s case, this is likely to be control-oriented red/white decks. He can also be used to fair effect in three colour decks that include red and white.