Cardinal Ollistra was a high ranking Time Lord involved in the Time War. A known associate of the War Doctor her official title is unknown, only described as "Arch-manipulator and Time Lord Stratagist".
Only the monstrous
the innocent
Ollistra first appears when a Time Lord reports the destruction of the Dalek fleet and the death of The Doctor. Horrified, Olistra laments Time Lord soldiers Bennus and Arverton when they allow the War Doctor to activate the Dalek-Time Destructor instead of them, a blast no Time Lord can survive. Ollistra attends the Doctor's funeral, sceptical of his demise.
personality
Ollistra is constructed as a heartless politician. Bennus and Arverton joke over the existance of Ollistra's emotions. Ollistra is also presented as truly patriotic, allowing Gallifreyans to sacrifice themselves for the greater good. Ollistra presents a discontent with the Gallifreyan armed forces, telling two soldiers "The Doctor is worth a hundred of you... people!". One could argue that Ollistra has become morally corrupt following her involvement in the Time War, Ollistra vows to destroy every Dalek before the Time War is over.
relationship with the war doctor
Although Ollistra respects the Doctor's efforts for Gallifrey, she is also seen to despise him. Ollistra describes the Doctor as "a thorn in your side. An embarassment for most of his lives." When he is presumed dead Ollistra confesses "Oh Doctor. I feel the universe is a far more dangerous place without you" commenting on either the Daleks' strength against the Time Lords or the freedom the Time Lords have to do the unthinkable and commit genoicde themselves now the Doctor cannot stop them.