Emperor Lei Shen (pronounced LAY-shen), also known as the Thunder King, was the first emperor of the mogu. After stealing the power of storms from the titanic watcher Ra, Lei Shen united the mogu clans into the first great mogu empire. Able to defeat even an August Celestial in combat, none were able to stop his goals of unifying Pandaria. During his rule, Lei Shen made several significant changes and contributions to Pandaria. The construction of the Serpent's Spine, the barrier separating the dreaded mantid from the rest of Pandaria's races, is often cited as his greatest achievement.

Recently, the Thunder King was resurrected by the mogu's Zandalari allies and attempted to unify the mogu once again, serving as the main antagonist in patch 5.2. However, the combined Shado-Pan, Alliance, and Horde assault on the Isle of Thunder put an end to Lei Shen's rule once and for all.