Granblue's G unit, Pirate King of Abyss, Blueheart & Ice Prison Underworld God, Cocytus Negative!

Pirate King of Abyss, Blueheart

Stride (Released when both players' vanguards are grade 3 or greater!)-Stride Step-[Choose one or more cards with the sum of their grades being 3 or greater from your hand, and discard them] Stride this card on your (VC) from face down.
[ACT](VC)[1/Turn]:[Counter Blast (1)] Choose up to two cards from your drop zone, call it to separate occupied (RC).

Granblue clan is a clan where focusing on reviving units from drop zone. Blueheart can be considered as a good G unit since he got an ACT skill with low cost to pay for reviving 2 units from drop zone. Honestly, this G unit is a must in every Granblue deck and with him a lot of combos can be made.

Ice Prison Underworld God, Cocytus Negative

Stride (Released when both players' vanguards are grade 3 or greater!)-Stride Step-[Choose one or more cards with the sum of their grades being 3 or greater from your hand, and discard them] Stride this card on your (VC) from face down.
[ACT](VC)[1/Turn]:[Counter Blast (1) & Put three cards from the top of your deck into your drop zone] If you have a card in your heart with "Cocytus" in its card name, choose up to one card from your drop zone, call it to (RC). Then, if you called a unit with "Cocytus" in its card name, you may choose a grade 1 or less card from your drop zone, call it (RC), and until end of the turn, that unit get [Power]+4000.

Based on my opinion, this G unit it's good to use with Ice Prison Hades Emperor, Cocytus "Яeverse". Since Cocytus "Яeverse" is more useful than Ice Prison Necromancer, Cocytus. However, you still can combo this G unit with Cocytus,

1) Ride Cocytus, use Cocytus skill, revive a Granblue from drop zone.
2) Stride Cocytus Negative, use another Cocytus or Cocytus "Яeverse" as Stride cost.
3) Use Cocytus Negative skill to revive back a Cocytus from drop zone. Then, you may continue to use his skill to revive another grade 1 or less card from drop zone.

Since Cocytus's skill can only be active once by placing it on (VG) circle. So, the cost for Counter blast 3 would be fair enough.