The only information I've seen is on hell hades (https://hellhades.com/new-fragment-fusion-incoming-versulf-the-grim/).  To be honest, I'm not impressed by the next one and will likely give it a miss.  I think it's supposed to be geared towards Magma Dragon, which is a Doom Tower boss I don't have any difficulties with already

Edit: It's also a fragment event, instead of a fusion one, which tends to be more annoying

Good  morning,

The  next  event  will  be  Versulf  the  Grim.  He  is  a  Knights  Revenant  HP  type  champion  who  will  be  Force  affinity.  The  event  will  start  on  July  2nd.  And  it  is  a  fragment  event.