Claws of Guthix is a combat spell in the standard spellbook. Casting it requires a Magic level of 60 in addition to having either a guthix staff or a void knight mace equipped. Casting it uses 1 fire rune, 2 blood runes and 4 air runes each cast. The spell is unlocked by completing the Mage Arena activity; it has to be cast 100 times within the arena itself in order to be used anywhere else. Upon a successful hit, Claws of Guthix lowers the target's Defence by 5%, this decrease does not stack nor will it reapply itself until the opponent returns to their base Defence level.
This spell is tied with Flames of Zamorak in price requiring 2 blood runes, 1 fire rune, and 4 air runes. Saradomin Strike costs 2 blood runes, 2 fire runes, and 4 air runes, rendering it the most expensive of the three god spells.
Note that since Claws of Guthix requires a Guthix Staff or a Void Knight Mace, rune-providing staves cannot be used.
Note 2: If using a Void mace and a guthix cape charge may still be used to hit up to 30.