Today we got another surprise line of Digimons revealed for BT-11, and includes our last SEC card. This line of Digimon was first introduced in Digimon World 3, and I believe has never existed outside of Digimon World 3.
I have not completed Digimon World 3.
The BEMmon line
Let's first take a quick look at this self-sustaining archetype: we have a total of 5 cards supporting this BEMmon archetype right now, starting with the LV3 BEMmon, LV4 Snatchmon, LV5 Destromon, LV6 Ragnamon, and the [Fusionize] option card.
This new archetype is all about digivolution. BEMmon is efficient when digivolved progressively from LV3 to LV6, requiring only 1 cost from LV4 to LV5 and similarly from LV5 to LV6, thanks to the inherited effect of a stack of BEMmons in your digivolution cards.
However, there is also this flexibility to warp digivolve your LV3 BEMmon into LV5 Destromon, or your LV4 Snatchmon into LV6 Ragnamon. Though more expensive, this pushes an instant solution whenever you need to destroy 1 of your opponent's tamer or Digimon this very turn.
Your LV3 BEMmons has 2 roles: to reduce digivolution cost and as ammunition for your LV6 Ragnamon. Under an ideal digivolution condition, we should have 9 BEMmons as digivolution cards on your LV6 Ragnamon, and this gives Ragnamon enough ammunition to divert 4 attacks to itself, or to prevent 2 deletion/return/put-to-security effects.
However when digivolving under less ideal situations, such as when warp digivolving from LV3 BEMmon to LV5 Destromon, it is quite unlikely that Destromon will have the 5 BEMmons needed in its digivolution cards to trigger a tamer-delete.
Another fact to note is that in this mechanic, LV4 Snatchmon appears to be the weakest link. Snatchmon fulfils a critical role of allowing LV5 Destromon to easily have 5 digivolution cards to trigger tamer-delete, but there seems to be a lack of effects that recycles Snatchmon from trash. Without Snatchmon, it might be a pain to stack enough BEMmons to put Destromon to good use.
The goal of this deck
This is essentially a tempo deck with flexible board control: use LV5 Destromon when your opponent is setting up tamers, and LV6 Ragnamon to remove any threatening Digimons on the field. The effectiveness of cost-efficiency and flexibility between these LV5 and LV6 Digimons may be more potent that it sounds.
But the goal is really to digivolve into LV6 Ragnamon, which has a powerful board presence (redirecting attacks and as a blocker), difficult to delete (unless you reduce its DP to 0), and passively aggressive (trashing your opponent's security at the start of your turn).
But with LV5 Destromon and LV6 Ragnamon being your only trump cards, 4 copies of each may not be enough. This is where the Fusionize option card comes in, offering additional digivolution consistency allow your Digimon to digivolve into Destromon or Ragnamon from trash!
Fusionize is also important since it allows to bypass the limited copies of LV4 Snatchmon during the digivolution process. Ideally with Fusionize, we can digivolve from a LV3 BEMmon to a LV5 Destromon from trash (may often not trigger tamer-delete) at 4-cost and then into LV6 Ragnamon with exactly 8 BEMmons in its digivolution cards to trigger a Digimon-delete.
Some known weakness
This deck seems to be weak against anything that removes digivolution cards, since LV5 Destromon and LV6 Ragnamon has strict conditions requiring a specific and ideal number of BEMmons as their digivolution cards in order to delete tamers or Digimons.
Without enough BEMmons, Ragnamon will also regress into a sitting duck LV6 Digimon.
Another obvious weakness is the fact that Ragnamon, with it's many ammunitions, is unable to deflect a single DP -15000 effect coming from Wyvern's Breath or DP -14000 from Chaosmon Valdur Arm.