Moon Staff

Wielded by Teclis of Ulthuan, the Moon Staff is imbued with the immortal power of the goddess Lileath, eternally youthful daughter of Isha, which flows through Teclis and invigorates his feeble frame. In times of great need, Teclis can call upon the full power of the Staff. Doing so allows him to unleash a fearsome barrage of magical power, or else dissipate dangerous sorcerous energies before they spiral out of control, but also leaves Teclis himself badly weakened.

Source

 * Warhammer Armies: High Elves (8th) -- p. 55