Merlanda was born 12 years after the opening of the Dark Portal and the outbreak of the First War in Lordaeron, to Lindara Emsworth and Hal Arynn. At a young age, the mages of the Kirin Tor discovered great magical potential in Merlanda, and so she was taken as a child to Dalaran to train. A quick learner, Merlanda had become rather adept in the arts of frost magic.
In time, Dalaran was moved to Northrend, floating above the Crystalsong Forest. When the war against the Lich King broke out in Northrend between the Alliance, Horde, and the undead Scourge, Merlanda - at the age of fifteen - had become a rather prominent figure in her class at the Violet Citadel. During the middle of the war, Merlanda was visited by her half-brother Drasgar Emsworth, now a commander in the Stormwind military, for a brief time before he traveled to Icecrown to combat the Scourge. Come the Argent Tournament, Merlanda spectated from the audience as her half-brother was a participant; this event became Merlanda's first true encounter with the ideologies of the Horde. When Garrosh Hellscream challenged the Alliance at the ring by sending down his champions, Merlanda found herself disgusted, and realized a hatred was starting to fuel itself once Drasgar had been wounded.
For the next couple of years in Dalaran, Merlanda's views of the Horde members of the Kirin Tor were generally negative; her behavior was not approved of by the higher-ups. After the defeat of Deathwing, the city of Theramore was bombed by the Horde under Warchief Hellscream. Later, when Pandaria was discovered by the now-warring Alliance and Horde, Merlanda requested that she be transferred to the front lines so that she may aid in the war effort, although in reality she wished to "punish" the Horde for their war crimes. However, with Jaina Proudmoore's claiming of leadership, the Kirin Tor joined the Alliance, and thus her request was accepted and she was teleported to Krasrang Wilds, where she worked with the Fourth Division to combat the Horde. Merlanda did not take part in the Siege of Orgrimmar, however after Hellscream's defeat she attended the fallen Warchief's trial in Pandaria.
Merlanda traveled to an alternate Draenor independently with two priorities: to combat the Iron Horde, and take action against Azeroth's Horde. Come the Assault on Tanaan, Merlanda found herself somewhat entranced by the powers of the Burning Legion, seeing it as a weapon to be bent and used in her favor. When the Legion invaded Azeroth for the third time, Merlanda traveled alone to the Broken Isles and attempted to absorb fel magics to use against the Horde. However the fel she had absorbed took over her and she was captured by the Legion; when she was released she had become a pawn of the Legion and was now working to weaken the Horde as an agent of Kil'jaeden. At one point the paladins of the Silver Hand arrived to Felsoul Hold during a mission to rescue Highlord Lyaria Silverdawn. During the battle, Merlanda encountered Drasgar, who led the paladins into the hold. The two briefly clashed when fel magics claimed her again and attempted to kill the paladin; Merlanda would have been successful had it not been for the intervention of the tauren Rakarus Brighttotem, who gave his life to protect Drasgar. Later, Kil'jaeden's control over Merlanda had failed after he was defeated over Argus, and she found herself caught on the Broken Shore by members of the Illidari, who captured her and turned her over to the paladins under Drasgar. Merlanda was freed by the Light's power, however still shaken by what had happened. Merlanda traveled to Stormwind City to recover incognito.
With the Burning of Teldrassil, Merlanda's hatred for the Horde was once again refueled and she turned to the army to offer her services. Knowing she could not return to the Kirin Tor given what she had done during the Legion's invasion, she hoped that her magic could be of use to the Alliance. Merlanda participated in the invasion of Tirisfal Glades as a battle mage, and was stationed in Brill during the Siege of Capital City.