Here's a tips for SatanSeal stage, a final stage.
To prevent you buying a lots of POTS, you can use this steps.
1) Bring any archer atleast lvl 70 or above, buy a lots of arrows.
2) After SatanSeal was opened, you may attack those satan with the archer.
3) If 1st and 2nd Satan was got killed by the archer, dont worry
4) After the 3rd Satan's HP almost died, make sure the archer stop attacking the monster
WHY?
1) Archer will stuck the Satans from attacking other players.
2) Dont have to buy a lots of POTS
3) For those dont have a good gears can use this steps
HOW?
1) Ok make sure that archer dont stop attacking the satan (except the last Satan when its almost died). Otherwise, the Satan will continue attacking other players.
Notes: Be alert when the arrows are finished.