Early service to ComStar
Both Adrienne and her brother Karl entered service with the Blessed Order. Sims rose to the rank of Precentor Oriente, serving on the Order's First Circuit during the reign of Primus Hollings York. One of the most notable detractors of York and his creation of ComStar Guards and Militia, Sims repeatedly engaged York in heated debates in the First Circuit over the funding for his pet project.
When a scandal accusing York of having an affair with well-known holovid actress Carrisa Sanders erupted in 2939, Sims argued that York soiled his holy post and pressed for his resignation, only to be caught completely off-guard when he named her his successor. With the potential of appearing too power hungry and overly eager to become Primus if she continued in seeking his resignation, Sims' verbal attacks completely ceased. 
Six hours after the violent assassination of the publicly beloved York at the corner-stone laying ceremony for the refurbished Sandhurst Royal Military College in 2947, the First Circuit confirmed Adrienne Sims as ninth Primus of ComStar. 
Primus of ComStar
Recognizing that she stood in the shadow of the charismatic York, her first act was to proclaim seven days of mourning for the fallen York. In a move that endeared her to the rank and file of the grieving Order, Sims also called for the canonization of him as a ComStar saint and proposed that Saint York be buried in the church floor of Sandhurst. Sims met each of the five leaders of the Great Houses who traveled to Terra for his funeral, assuring them that under her rule ComStar would do everything possible to assist them in finding a means of peaceful coexistence. 
Despite these proclamations of peace, among her first orders was to reverse the winding back of ROM and authorize expanded resources and funding which a grief stricken First Circuit quickly approved.  Whether the shadowy intelligence organization directly or indirectly caused the assassination of the openly hostile York, the increase of funding and elevation of her brother Karl to head the branch helped ensure ROM totally supported her and she in turn referred to it as the core and essence of preserving ComStar.
After the events resulting from her elevation to the post, Adrienne Sims' tenure as Primus was relatively quiet until 2959, when she began to suffer horrible nightmares and visions of Jerome Blake and Conrad Toyama overtly warning about the destruction of Inner Sphere by strange beasts from beyond the Periphery.   
At first horrified when she revealed her visions to them, the First Circuit convinced Sims to take a six month leave of absence and seek professional help, with Precentor Dieron Stephanie Hendricks acting as Primus in her place. However psychological counseling found no signs of mental dysfunction in Sims and placed her on a stress-relief program, but the visions continued unabated even after Sims returned.  
Sims' enemies on the First Circuit now leaked word of these visions to the Order's rank and file members in an attempt to taint her as mentally unstable. However in the mystical ways of the Blessed Order meant that many interrupted Sims' visions as a sign from the Blessed Blake himself and began hailing the Primus as a prophet. 
On the back of her strengthened popularity and motivated by her visions, in November 2959 Primus Sims proposed the creation of a new branch of ComStar tasked with scouting and mapping the worlds beyond the known Periphery. Rather than cite her dreams in seeking approval from the First Circuit for funding for the Corps, Sims instead referred to the mystery of Kerensky's Exodus Fleet, pointing out the terrible threat to ComStar's position of technological advantage if their descendants ever returned unannounced.   
Death and Legacy
Adrienne Sims died abruptly in her sleep in 2979.   While she had weakened as her visions became more frequent and pronounced, her death was still unexpected and she had not named a successor. After ordering her body cremated and her ashes scattered in deep space by an Explorer Corps JumpShip, the First Circuit selected Yin Takami from their number to the post. 
The most lasting effect of Sims' tenure as Primus was the introduction of the Explorer Corps. While a public relations boon, enhancing the Order's scientific knowledge, it also allowed ComStar to recover untouched SLDF caches and ensure further expansion of the Word of Blake. However, while she hoped it would prevent the future predicted by her terrible visions, it was among the greatest ironies that the Corps in fact triggered the Clan Invasion when the Outbound Light discovered Huntress in 3048.
While few believe Sims possessed true psychic powers, letters and notes from Sims on her visions feature frighteningly specific descriptions of a horde of strange monsters that can be interpreted as the insignia of the Clans, including a "metallic viper" (Clan Steel Viper), the "emerald birds of death" (Clan Jade Falcon), the demon horses (Clan Hell's Horses) and a "six-legged bear" (Clan Ghost Bear).  
Canon Rumors hold that Sims' "visions" actually stem from knowledge of the Clans supplied by elements of the Annihilated Clan Wolverine harbored by ComStar, or otherwise from clandestine contact with the Clans.  
|Primus of ComStar
| Succeeded by|
- ComStar, p. 42
- ComStar, p. 44
- ComStar, p. 43
- Explorer Corps, p. 6
- Second Succession War, p. 87, "Legacy of Destruction - The Threat from Beyond"
- ComStar, p. 45
- Explorer Corps, p. 7