"Pattern"

Legendary Resistance (2/Day). When "Pattern" fails a saving throw they can choose to succeed instead.

Immovable. "Pattern" is immune against any form of forced movement.

Phase 1: (291 HP - 170 HP)
Recognition. At the start of "Pattern's" turn each player gets marked by a specific symbol, until the marks are resolved "Pattern" is resistant to all damage. At the next beginning of "Pattern's" turn these marks get resolved.
0 wrong: "Pattern" loses its resistance to all damage.
1 wrong: "Pattern" loses its resistance to all damage, but all enemies take 2d6 force damage.
2-3 wrong: "Pattern" retains its resistance to all damage and all enemies take 4d6 force damage.
4-5 wrong: "Pattern" is immune to all damage and all enemies take 8d6 force damage.

Phase 2: (170 HP - 0 HP)
Restricting Prism. At the start of "Pattern's" turn, one player gets teleported in the beam line, they have their movement speed reduced to 0 and can't teleport. This effect lasts until the end of "Pattern's" next turn.

Symphony. After Restricting Prism, "Pattern" presents 3 symbols in a random order. Then 3 players get marked with these symbols. A marked creature emanates a 10ft. aura. A creature entering this emanation or starting its turn in it takes 4d6 force damage, except the marked creature. The marked creatures take 2d6 damage at the start of their turn.

Purification Beam. "Pattern" channels a Purification Beam for 1 turn, targeting the player under the effect of Resitricting Prism. At the start of "Pattern's" next turn the beam fires. Depending on how many players marked by Symphony, are in the line, the following effects happen, these effects also happen when the marked players are in the wrong order as shown by "Pattern":
1 Player: The target of Restricting Beam takes 8d6 force damage, the marked player takes 4d6 force damage and has its mark removed. The other marked players retain their mark and the damage at the start of their turn increases to 4d6.
2 Players: The target of Restricting Beam takes 4d6 force damage, the marked players take 2d6 force damage and have their mark removed. The other marked player retains his mark and the damage at the start of their turn increases to 4d6.
3 Players: The target of Restricting Beam takes 2d6 force damage, the marked players lose take 1d6 force damage and have their mark removed.

If the player, that is not under the effect of Restricting Beam and not marked, is in the beam line when it fires takes the same damage as the player under the effect of Restricting Beam.
Players in the aura of the mark take an additional 2d6 force damage when the mark is removed.

Multiattack. "Pattern" makes 2 Chaining Prism attacks and 1 Ripple attack.

Chaining Prism. Melee or Ranged Attack Roll: +9, reach 10ft. or range 90ft. Hit: 2d10+5 force damage. When this attack hits, it targets the closest 2 enemies as well, these creatures make a DC16 Dexterity saving throw. Fail: 1d10+5 force damage, Success: half damage.

Ripple. "Pattern" chooses a point within 90ft. range. All creatures inside a 10ft. sphere around that point make a DC16 Constitution saving throw. Fail: 2d10 thunder damage and the prone condition. Success: Half damage only.

Elsewhere. "Pattern" targets two creature to make a DC16 Wisdom saving throw, a creature under the effect of Restricting Prism cannot be targeted. Both fail: They swap positions. 1 Fail: The creature is frightened by "Pattern", another creature can use it's action to break the affected creature ouf of the effect. An affected creature can make a DC16 Widsom saving throw at the end of their turn to break free by themselves. Success: nothing happens.

Try Again!. When "Pattern" would be hit by an attack roll it can use it's reaction to force a DC16 Consitution saving throw from the attacking creature. Fail: The creature gets teleported 20ft. away from "Pattern", if the attack would be out of range the attack doesn't hit. Success: The attack receives disadvantage.

"Pattern" can take 2 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The Oracle regains spent legendary actions at the start of her turn.

Chain Beam. "Pattern" makes one Chaining Prism attack, but it only chains to one additional creatures instead of two.

New Perspective. "Pattern" targets one creature to make a DC16 Intelligence saving throw. Fail: The creature takes 3d6 psychic damage. Success: The creature gets a brief vision of it's own role in the next round.

Reconstruction. One quarter of the room becomes difficult terrain until the start of "Pattern's" next turn.