A Photon Caster is a Tau defensive technology that all XV9 Hazard Battlesuits have mounted upon their forward knee armour. Operating in a similar fashion to Photon Grenades, Photon Casters are designed to be used in the situation that enemy forces advance too close to the Battlesuit, and repel attackers with a dazzling pulse of multi-spectrum light and a deafening sonic burst. This will often blind and disorient attackers, confusing them and slowing their charge so that the Battlesuit is able to respond with further volleys of lethal firepower.
- Codex: Tau (3rd Edition), pg. 19
- Codex: Tau Empire (4th Edition), pg. 29
- Codex: Tau Empire (6th Edition), pp. 37, 67
- Imperial Armour Apocalypse 2, pg. 58
- Imperial Armour Volume Three – The Taros Campaign, pg. 80
- Warhammer 40,000: Rulebook (6th Edition), pg. 62
- Warhammer 40,000: Wargear (4th Edition), pg. 54