As soon as Decimator Beetles ability resolves, state-based actions are checked, and the game sees that you have both counter types on your Servant, so one +1/+1 counter and one -1/-1 counter are removed at the same time (resulting in Servant dying)
Banned Pair Cards: Two cards (Card A and Card B) that cannot be included in the same deck together
Deathtouch and double strike arent a bad idea, and you can use red damage doublers and extra combats to seal the deal
Unlike the other Arcanine from this set, this Arcanine doesn't have an Ability, but it does have two moves, the first move is called Crunch and for two energy cards, one each of fire and colorless, it does 30 damage plus if you get a heads when you flip a coin your opponent much discard an energy card attached to their active Pokemon
(1) Special Summon 1 White Woods monster from your hand or Deck, then, immediately after this effect resolves, you can Synchro Summon 1 White Woods monster