Regardless of the archetype pairing, Regenesis just offers a formidable grind game with its ability to come back over and over again
However, I want to acknowledge the following rule for the Commander format: Rule 13: Abilities which refer to other cards owned outside the game do not function in Commander without prior agreement on their scope from the playgroup. Karn is a really good card for any 60-card format because you are allowed a 15-card sideboard from which you can pick cards that are "outside the game." However, in Commander, there are no sideboards or wishboards
For example, the Summer TCG set includes cards based on Pokmon GO's PokStops, Lure Modules, and the mobile game's infamous Ditto disguise feature
You and others can attack it
Without cards like Skill Drain, Malefic Decks tend to only get a single attack each turn
These include the normal summon/set of one monster (in face-up attack position or face-down defense position respectively), any special summons you are allowed, the activation/setting of spells and traps, and changing battle positions of your monsters, including flip-summoning facedown defending monsters into the face-up attack position