Xenagos, God of Revels
Xenagos is great commander for Gruul providing haste and doubling power of a single creature. The indestructible combined with being sometimes an enchantment makes Xenagos very difficult commander to deal with.
Xenagos is definitely a great Gruul commander with cEDH power level as the ceiling due to the easily achievable infinite combat steps and beating every opponent out in a single turn with combat damage.
Themes for Xenagos, God of Revels
Stompers
As green has the best mana ramp options in the format, and the biggest creatures, too, it is only natural that big creatures / stompers decks are popular in mono green. Stomper decks have lots of ramp in them, and aim to cast big creatures to wreak havoc to the opponents.
extra combats
Decks with heavy focus on "at the beginning of combat" triggering commanders synergize well with extra combats. Extra combats decks' main strategy is often multiple extra combats or even infinite amounts with a combo!
Hydra tribal
Hydras are greens biggest and baddest creature type with many different creatures. Hydras are many-headed snake-like creatures and are often x-spells, where the spent mana is turned into a massive, single creature. Hydra decks creates massive creatures to attack and receives benefits from power-related synergies.
Dragon tribal
Dragons, alongside Goblins, are reds primary creature types. Dragons are reds strongest creatures and most of the expansions have some kind of red dragon in them. As dragons are expensive to cast, dragon tribal decks run multiple cost reduction effects and have ways to cheat the expensive dragons on the battlefield.
