Cosmo Fiend: Rosen

Cosmo Fiend: Rosen

Type

Rosen's Cut-In

Description

Rosen is the final boss of Fiend War and the strongest one in Cosmofiend. If he finds a strong opponent, Rosen will personally fight them in his own universe with planets rotating around himself. Using the force of these planets, Rosen split himself into two halves being Black & White Universe.

Move Set

• Hex Panel Transformation: When all parties in their respective universe enter Rosen's room. he'll transform the ground similar to Executioner Belial's Tile Transformation that lets him use Hex Pillar depending on his hand movement and regardless of what planet phase he's in.

• Planets Phase: Rosen summons four different planets that rotate around him as they are shared among both parties Universe-wise and he'll consume one of those planets that activates a phase with different patterns in a non-randomized order.

• Flame Planet: During this phase, Flame Floor is enabled and every hex panel that party members step on becomes ablazed. Standing on the ablazed hexes will cause heavy damage similar to a  Burn (Status) effect. At a certain period of time, Rosen can create Hex Explosions from those ablazed panels. Have all four party members spread out in the corners during this phase, use  Leap and keep jumping until the duration wears off and carry plenty of Healing Kits until the phase is over. After 20 seconds, every ablazed hex will explode and all party members should gather in the center as Rosen becomes groggy for 10 seconds.

• Glacial Planet: Rosen can be damaged at almost any time during this phase, but cannot become groggy. During Glacial Planet, the "A cold wind is blowing" gauge appears above each player's head and slowly fills up by itself. Each time a skill that requires  Clear Cube Fragments is used, the gauge fills up faster. When filled, the gauge will activate Crystal Prison, which traps the player inside. Additionally, anyone in close range will be inflicted with  Frozen (Status), which can be negated with a  Toy of Sparkling World. After a short time, an empty crystal of the same color will spawn somewhere in the room. Party members must break the empty crystal, or else the trapped player's HP will slowly drain until they die. Rosen will also attack players with Ice Spikes with his hand movements, including a room wide variant. The room-wide variant is the only time that Rosen is invulnerable during this phase.

• Transcendent Planet: Rosen is effectively invulnerable during this phase due to his extremely high defense and elemental resistances, and he'll use Transcendent Hex Pillars that deal low to moderate damage and can interrupt players. After a few a seconds, Rosen will summon six Elemental Crystals that are spread out across the room. These crystals can be hit and each time this occurs, they'll change the element going from (Fire -> Water -> Light -> Shadow) In order to damage Rosen during Transcendent Planet, all party members must match the crystals to the element that was decided on before entering either Universe -- red crystals for fire, blue crystals for water, yellow crystals for light, or purple crystals for shadow. If successful, Rosen becomes groggy for 10 seconds and only takes damages from that chosen element only. If the timer gauge fills up and the party was unable to match the crystals, Rosen will teleport to the middle and summon Hex Explosions for a short while until the crystal pattern is re-summoned again. Notably, certain things seem to be able to damage Rosen even when he is "invulnerable", including the dash attack proc from the Merciless Ruler Set.

• Storm Planet: Like Ice Planet, Rosen is vulnerable the whole time during this phase and uses wind-based attacks throughout the entire room.
  • Hex Tornadoes: Like any other Hex Panels, he can summon a wind version of this in random spots of the room.
  • Small Green Tornado: Rosen sends out three waves of these that deal low damage, but strong enough to push players back into the huge tornadoes.
  • Tall White Tornado: Rosen summons four of those to chase after players that can capture and throw them into the room's Hex Tornadoes.
  • Whirlwind: A large green circle appears below Rosen and he creates a whirlwind that pulls in everyone in the center as well as the room edge's tornadoes that can easily kill anyone if not avoided. Recover with Healing Kits or have the Crusader/Enchantress use  Healing Wind/ Regenerative Aria/ First Aid of Love to avoid casualties as Rosen enters his groggy states for 10 seconds before repeating the patterns. Enchantresses can also use  Black Forest Brier to keep party members safe during this pattern, though it requires good timing.

• Standby: If only one party entered The Gate or the last planet is still being dealt with by the other party, this means there are no more planet phases to fight. Rosen transforms the room back to normal, summoning dusky hex pillars and remaining invulnerable at all times until the other party destroys the last planet. This non-phase can be useful for players to "hard reset" if they used up their skills during the fight. However, only six  Life Tokens can be used by each party, so they should be used sparingly. The 10 minute time limit should be kept in mind as well. Note that unlike the Transcendent Planet phase, Rosen is truly invulnerable here and cannot be hit at all, meaning certain classes like Enchantress and Rogue cannot build up stacks of their resources that require hitting enemies -- Enchantress cannot gain Hex Dolls with  Harvest/ Garden of Pain, and Rogue cannot build up  Silver Stream stacks.

Once all four planets are destroyed, Rosen immediately enters his main groggy phase and becomes vulnerable. Both parties from Black & White Universes have 15 seconds to deal as much damage they can to Rosen in one cycle before the phase ends to clear Fiend War. If either party didn't manage to defeat Rosen, he'll equalize the HP between both universes and start up a second cycle, re-summoning all four planets.

Strategy

• Before entering either The Gate's Black or White Universe, both parties should decide on what element to choose for Rosen's Transcendent Planet phase. For example, if you're the main damage dealer for party 1-4 that wields a high  Water Element attribute and 5-8's main dealer specializes in  Shadow Element, everyone else should switch to that element by using a Cube Contract and selecting a specific cube color.
  • This doesn't bother classes like Elementalist, Elemental Bomber or Sword Master who can use all four elements with their skills, but it's still recommended either way.

• Due to Fiend War forbidding cooldown-related consumables and equipment, hard resetting is the only way for both main damage dealers or Crusader/Enchantress to regain their skills by dying to Hex Pillars and revive with a  Life Token.

• Bring at least two Physical Enhancement Potions for Rosen's main groggy phase and during Rush only if your party was unable to 1-cycle him and starts up a second one.

• Learn one level of  Leap to avoid Flame Planet's Fire Floors. Classes such as Female Spitfire's  Nitro Motor & Dragon Knight's  Dragon Wing can also avoid the ablazed hexes.

• Using  Hammer of Repentance/ Purifying Lightning is very helpful against Rosen during Storm Planet as it puts him in repentance mode for a short period of time, making the planet's patterns less frustrating.

• If you have a Savior's Triumph Weapon (excluding Crusader/Enchantress), the explosion effect's range could possibly help with the Crystal Prison pattern during Glacial Planet.

• Most parties often skip Glacial Planet due to how difficult the phase is and asks the Crusader/Enchantress to deploy their  Apocalypse/ Crux of Victoria/ Marionette if they get the planet first.

• There are two different tactics that both parties can use when facing Rosen which are Rush & Delay depending on the Planets phases are either in:
  • Rush: First planets normally count during this so clear it soon as possible. If the second planet is destroyed, wait for the other party during Standby.
  • Delay: Chip away at Rosen's HP by using sustained skills, but do not kill him depending on which planet phase he's in since Storm & Transcendent Planet are very time consuming and both phases requires cooperation from either party to make sure either side is prepared to defeat Rosen when he enters his main groggy phase as delaying can be useful for hard resets.
    • But since the planets are randomly picked, both parties can either rush any planet if they are strong enough to 1-cycle Rosen or prefer to delay if one party needs more time to prepare.

• In Guide Mode, since no other party members are around to free the player if they get trapped in a Crystal Prison during Glacial Planet, the player needs to clear the planet before their gauge fills up, or else they will inevitably die. This is particularly troubling for new players, since they may need to use all of their skills to defeat Glacial Planet Rosen and thus won't have any skills available to use during Rosen's main groggy phase. Thus, it may be wise to whittle Glacial Planet down to low health, then hard reset before clearing the planet.

Appearances

• Fiend War (Boss)

Gallery

Notes

• Due to high pings and lag, Rosen can suffer from a number of bugs that will not only hamper his fight, but hurts the entire raid's progress as a whole.

Trivia

• While he does seem to have voice dialogue, they were never used upon the Raid's release.
• Rosen's name is derived from Christian Rosenkreuz, legendary founder of the Rosicrucian Order.
• Rosen may possibly represents all the elements:
  • Flame Planet - Fire
  • Glacial Planet - Water
  • White Universe - Light
  • Black Universe - Shadow
  • Transcendent Planet - All elements
  • Storm Planet - No element