Heart of the Oak runeword (HotO)
Heart of the Oak is a Diablo 2 Resurrected runeword created by combining ko + vex + pul + thul into a 4 socket staff or mace. It requires at least level 55 to equip.
Heart of the Oak is a very popular runeword. It is most often used by caster builds because of its +3 to all skills, high bonus to faster cast rate, and resistances.