Latosius was one of the senior members of the Moon Guard when the War of the Ancients began. An elderly night elf, he had practiced sorcery for a very long time, and he considered himself one of the foremost spellcasters of his order.
He was one of the sorcerers dispatched to Black Rook Hold, the fortress of Lord Kur'talos Ravencrest, in order to interrogate the prisoners Malfurion Stormrage, Broxigar, and Rhonin. Malfurion told a wild-sounding story about how the Highborne were abusing the Well of Eternity. Like many lower-caste night elves, Latosius was willing to believe ill of the Highborne. Like most of night elf society, though, he did not regard Queen Azshara in the same negative light, despite the fact that she, too, belonged to the Highborne.
When the Burning Legion and its mortal allies managed to restrict access to the Well, the disruption brought an abrupt end to Latosius' magical interrogation of Malfurion. The Moon Guard tried repeatedly to restart the interrogation, but their spells failed without direct access to the Well's energies. Latosius was frightened and furious.
A Valiant End
Messengers began arriving at Black Rook Hold with even worse news: demonic invaders were attacking Zin-Azshari. Kur'talos and his soldiers were convinced that the queen had become a prisoner in her own palace. They therefore set out for Zin-Azshari to free her and defeat the demons. Although the Moon Guard's magical abilities were greatly diminished, Latosius and his comrades accompanied the army.
The war escalated, and as the highest-ranking sorcerer, Latosius assumed leadership of the Moon Guard and directed their efforts on the battlefield. However, several other defenders later remarked that Latosius seemed to focus too much on minor details rather than the bigger picture. Eventually the elderly sorcerer was caught off guard and killed by an eredar warlock's spell.
Rhonin avenged Latosius' death by killing the warlock responsible. By the time Rhonin had done so, Illidan Stormrage was already crossing the battlefield toward the remaining Moon Guard. Illidan, though not a member of their order, clearly had superior magical talent, and he proved much better than Latosius at coordinating the Moon Guard's efforts.