Anguish

Anguish is an Ancient curse that requires 95 Prayer to activate, the highest alongside Turmoil and Torment of all prayers in the game. It can boost the user's ranged accuracy, ranged damage, and Defence significantly, as well as drain those of opponents, making it the strongest Ranged-boosting prayer in the game.

Effects
Anguish adds 10 levels to Ranged when calculating hit chance, adds 10 levels to Defence, and boosts ranged damage by 10%; it drains opponents' Ranged when calculating their hit chance by 6 to 10 levels, drains their Defence by 6 to 10 levels, and drains their ranged damage by 9% to 15% (6% to 10% in PvP). The boosts to the user are constant, but like leech curses, the draining of opponents must strengthen over time.

A player will gain the same ranged and defence bonuses regardless of an enemy's class, but Anguish cannot lower its damage or accuracy if it does not use ranged. Note that most high-level bosses cannot be drained by Anguish or any ancient curse.

Sap and leech curses cannot be used alongside Anguish.

Anguish and Rigour
Anguish is often compared to the prayer Rigour, which is the strongest Ranged prayer on the standard prayerbook. Rigour requires 70 Prayer, 70 Defence, and completion of the Knight Waves Training Grounds; Anguish requires 95 Prayer and the Temple at Senntisten quest.

If comparing stat increases, Anguish is not much stronger than Rigour, yet Rigour lacks the ability to drain enemy stats while Anguish can drain them strongly. Also, the healing curse Soul Split can be used on the Ancient Curses with 92 Prayer and provides another incentive to use the book.