Mettaton NEO was added during Beta 4.3 as a new Legendary card. After multiple effect changes and discussions, he was finally added to the game with the effect of dealing his attack as damage to all enemies upon dying, but cannot attack himself. However, as of Beta 11.0, it now also deals that damage to ally monsters.
CombosBest used in Bravery, Patience, Perseverance and Justice, all with different strategies. Keep in mind that you might want to leave your board as empty as possible before executing these:
- Bravery: Increasing his ATK with Strength. (Snowdrake with other SOULS.)
- Patience: Giving him Taunt with Protection. (Glad Dummy with other SOULS.)
- Perseverance & Justice: Using Worsening & Punishment/Shootout respectively to kill him. (Loox or Vulkin with other SOULS.)
People using Kindness may want to use cards like Force of Nature and then Longevity to prevent NEO from dying if their opponent has it, but a better solution (and not just in Kindness) is by Silencing him with cards like Nacarat Jester to remove his ability.
Another good strategy with any class it using it with Hot Dog Vulkin, which works as a Snowdrake and Vulkin in one for 5G, and as such will give +2 ATK to NEO as well as kill it, but also deal that increased ATK as damage.
Because of the various uses of the card, NEO can be very influential in the battlefield in terms of affecting the enemy and how they use cards as well as how you create your own deck. For those using Bravery, keep in mind that Final Charge will not work on cards such as NEO who can't attack unless you used Asriel or have Will.