Boss 4: Soul Light

Setting
The players explore the crypt, and see the half-dead sister on an altar. Her soul is being drained, and the players need to restore her soul to awaken her. Thematically, the light of her soul is being dimmed, and has to be restored. The fight therefore revolves around taking action to combat the dimming, and taking action to restore light.

Overview
A crypt fiend is draining the soul of the sister. It periodically casts an AoE that damages everything in its line of sight. The crypt fiend has to be tanked in sight of the sister for her soul light to increase damage done, but has to be moved behind a pillar for the AoE.

Hardmode
On hardmode, a very large add needs to be dealt with. It takes 99% reduced damage, and so do the small adds. When a large add dies in proximity to a reality anchor, it deals a lot of aoe damage, and damage reduction effects on enemies are removed. The tank should require cooldowns for the vulnerability phase, and the healer should require a lot of aoe healing outside of the vulnerability phase. That way, the healer can damage the very large add as well, while still having either the tank or the group threatened at all times. To win the encounter, all three reality anchors must dissipate, and the very large add must be killed. If the very large add is not killed before the last vulnerability phase ends, it enrages. The small adds should not have enough health to allow for three funnel DPS specs.

Abilities

Soul Light: The sister periodically casts Soul Light, which increases damage taken by all enemies hit. As her soul is restored, this effect grows in potency

Diminish Soul: The crypt fiend periodically casts Diminish Soul, which damages everything in line of sight.

Hardmode Abilities

Soul Shadow: When the Diminish Soul cast finishes, the crypt fiend places a shadow zone on the ground. Casting Diminish Soul within a Soul Shadow causes the spell to ignore line of sight, and hit everything.