Esior provides protection and evasion in the command zone, while Ardenn gives you utility and cost reduction by effectively removing equip costs
A creature with triple strike deals combat damage up to three times per combat: once along with other creatures with first strike (or double strike or triple strike), again with creatures without those abilities, and again along with creatures with last strike (an Un- game exclusive)
I think this is an important sideboard tool for red decks that are looking to take a more controlling position against creature decks, and while Rabblemaster is not very strong against something like Elves, this card would be especially brutal there
Accelgor's attack causes two status conditions, as it makes the opponent's active Pokmon confused and poisoned, which can make it difficult for the opponent to attack on the following turn
On top of that, it punishes aggressive and card-hungry opponents by letting you draw whenever they attack with multiple creatures, draw their second card, or cast their second spell during a turn