Effect1: [On Play] You may put up to 5 red or black LV5 Digimons with different card numbers and [Cyborg] in their type from your hand or trash into this Digimon’s digivolution cards. Gain +1 memory for each card placed.
Effect2: [Both Turns] This Digimon’s DP cannot be reduced.
Effect3: [Both Turns] When this Digimon would be deleted, you may trash 2 LV5 digivolution cards from this Digimon to prevent it from being deleted.
Mugendramon has a unique first effect, and semi-unique second and third effects. With his first effect, he can be considered as a conditional 7-cost-to-play LV6 Digimon – a rather easy condition if you build your deck around him. LV5 Digimons generally have great inheritable effects, and being able to put (up to) 5 of those Digimons as his digivolution cards will generate insane value. The drawback: not only do they have to be either a red or a black [Cyborg] type, but also of different card numbers.
Meanwhile, his second effect gives him immunity towards DP reduction, an effect shared only with [BT6-053] Eldradimon. His third allows him to trash 2 (LV5) digivolution cards to prevent deletion, an effect with some similarities to [BT5-086] Omegamon. These effects when put together in a package, make Mugendramon one of the hardest Digimons to remove!
It is obvious that these 4 [Cyborg] type Digimons (revealed 2 hours before Mugendramon) were meant as direct supports: they not only provide good and stackable inheritable effects, but also mill for Mugendramon. However, I believe that they are not the only candidates for the Mugendramon engine.
[ST5-11] Megadramon and [BT6-061] Gigadramon are also [Cyborg] type Digimons that I believe will supercharge the Mugendramon engine in a megazoo setting.
Kaiser Nail - Match Made In Heaven?
In addition, the LV7 that Mugendramon originally digivolved into (before pulling with Kaiser Nail) will have up to 5 LV5 digivolution cards, and while the EX-01 digivolution cards may not do anything for the LV7 Digimon (since there is no [Machine] type LV7 yet), the [ST5-11] Megadramon and [BT6-061] Gigadramon, if inherited, will grant your LV7 Digimon <Blocker> and a +2000 DP buff!
Return of Ragnalordmon?
To take advantage of inherited <Blocker> effects, it is possible to digivolve into a LV7 with <Reboot>, and the only candidate that comes to mind being [BT3-019] Ragnalordmon. With both <Reboot> and <SecurityAttack+1>, he can play the role of both sword and shield (and not to mention a 0-cost digivolution if you have either Durandamon or BryweLudramon in hand).
To take advantage of your stack of (probably useless) LV5 digivolution sources (because your LV7 is no longer a [Machine] type Digimon), it is possible to digivolve Mugendramon into [BT3-112] Alter-S, and subsequently into [BT5-111] Omegamon X. This way, ideally, Omegamon X should have at least 6 digivolution cards (Alter-S and 5 other LV5 cards, assuming Mugendramon was either returned to hand by Alter-S or pulled using Kaiser Nail) allowing him to negate up to 3 attacks!. It is also good strategy to use Omegamon Zwart when this card can help to trash more cards and play 2 LV5 or lower from trash, widen the board.
For once, you can even play [BT5-110] All Delete and Mugendramon will be able to survive this option card by trashing 2 digivolution cards!
When playing a deck full of blockers and inherited blockers, then it helps to also play [BT3-075] Craniamon for support! Imagine a 16000 DP Ragnalordmon or 17000 DP Omegamon X with <Blocker> that is immune to deletion effects!
A boring Digimon choice for SEC, with a very unique and interesting set of skills! This is the new EX-01 Mugendramon! Good luck with your pulls!