Well i'm a bit worried of it.
They said it's based on Colisseum event but in this one cards won't be boosted by the E gacha. Instead the boost will affect the shards you recieve.
They also said that you will buy prizes with the shards.
If they do the current multiplier again... will mean that a full e gacha slayer guy will buy 40 + x times more than a f2p ?
If this is the case then the balance we had till now will totaly be broken in this event.

there was no balance in coli with slayers

They'll win for sure, but the box is cleared in the same time. So way less impact on prizes.

I thought Shards will be just a replacement / analog to Medals or Coliseum Gacha Tickets...

If shards is an event how can revival take place after its start by 1 day only?! can it be 1 day event ?

they said revival will take place between events so it may not be an event

I think they will take their usual rest ( 3 ~4 days) before heavy duty event such as Coliseum .

since the game undergo EVENT manintainance

two possible outcomes

1. it can be a new kind of event or it maybe the one replacing perocolo ( i hopes its not the latter one )

2. it can be a mini event running for 1 to 2 days

It's replacing perocolo I guess, because you go against other players. Only this time the slayers don't boost your SED, but the shards you get that drop from your opponents.