Thomas Lysander is introduced as a jolly teacher, passionate about literature and history.
During a NG+ exclusive quest in Trails of Cold Steel II, he asks Rean Schwarzer to find the Black Records. Upon having Thomas decipher these, they discover the records contain the unabridged version of the War of the Lions.
Completing this quest unlocks a special scene on the rooftop of Thors Military Academy, where Thomas creates a so-called "partition", which creates a room separated of the actual time-space continuum, to have a talk with Rean and Rosine. There he reveals his identity as the Second Dominion of the Gralsritter and re-introduces Rosine as his squire. Because Rean is the Awakener of Valimar, a fragment of the Great Power, Thomas asks Rean for his cooperation.
After the partition resolves and Rean leaves the rooftop with Class VII, Thomas comments to Rosine that Rean's assistance is needed in uncovering Erebonia's two Sept-Terrion and the secrets of the Divine Knights system fashioned by the Hexen Clan and gnomes. He also reveals that he and Rosine are in charge of eastern Erebonia while Barkhorn takes care of western Erebonia.
|Sen no Kiseki|
Thomas teaching history class
|Sen no Kiseki III|
|Dominion||Ein Selnate - Thomas Lysander - Kevin Graham - Barkhorn - Wazy Hemisphere|
|Knight||Rufina Argent - Abbas|
|Squire||Cesar - Juno - Marcia - Ries Argent - Rosine - Scarlet - Ventus|
|Cathedrals||Grancel - Crossbell - Heimdallr - Bareahard - Roer - Haliask - Ardent|
|Chapels||Bose - Rolent - Ruan - Zeiss - Trista - Celdic - Legram - Reeves|
|Concepts||Aidios - Artifact - Gehenna - Gralsritter - Merkabah - Sept-Terrion - Stigma|