Ergo Glast is the leader of the Perrin Sequence Syndicate. He represents them in all their dealings with the Tenno, and also assigns the quest The Glast Gambit.
As the leader of the Perrin Sequence, Glast represents the Syndicate in its dealings with the Tenno. The Perrin Sequence is described thusly:
A collective of brilliant and powerful merchants, splintered from the Corpus. Their goal is to restore order by bringing prosperity and direction to the violent world they study.
Following their own doctrine to achieve Profit, the Perrin Sequence have turned away from the Corpus ideology that conflict must be capitalised upon. Instead, these merchants search for ways to exercise their trade without instigating violence.
The Perrin Sequence sells the Secura line of weapons: the Secura Penta, Secura Dual Cestras, and Secura Lecta. They also carry weapon augments for the Grinlok, Acrid, Spectra, and Lanka, and warframe augments for Banshee, Chroma, Inaros, Ivara, Mag, Nekros, Nidus, Revenant, Rhino, Trinity, Valkyr, and Vauban. The Syndicate ranks, from least to most favoured, are Write-Off, Liability, Neutral, Associate, Senior Associate, Executive, Senior Executive, and Partner. The names of their sigils, in ascending order of importance, are Progress, Opportunity, Calculating, Synergy, Directives, Strategy, Tessellations, Optimum, Capital, and Chairman. The Perrin Sequence sell Captura scenes for the Corpus Gas City Conduit, Ergo’s Boardroom (their headquarters in the Relay), and the Mycona Colony (from the Glast Gambit quest).
Greeting the Tenno
(if the Tenno is Neutral rank) “The Perrin Sequence reject the Corpus doctrine that conflict is opportunity. We see the numbers differently. A shared prosperity can bring a shared peace.”
(if the Tenno is Executive rank or higher) “We stand behind you. Let’s build a brighter future.”
(if the Tenno is Liability rank) “Are you betting against us, Tenno?”
(if the Tenno is Write-Off rank) “The probability of us working together has converged on never.”
“We must raise more capital to pursue our goals.”
(after a successful sacrifice) “Congratulations, Tenno, on your promotion. Much deserved.”
“These are our best deals.”
“This is what we offer.”
“These are a bargain, just for you.”
Purchasing an item
“You have excellent taste.”
“You scratch our backs, we’ll scratch yours.”
Beginning Syndicate mission
“Your calculated survival probability is encouraging… good luck.”
When sending death squad
“We Perrin always collect our debts.”
“We’ve decided that you are bad for business.”
Ergo Glast has additional dialogue in the Glast Gambit quest, where he is named for the first time, as well as in Operation: Ambulas Reborn, where he plays a significant role, and Operation: Rathuum, where he asks the Tenno to turn over Grineer defectors so they can answer for their sabotage of Perrin Sequence property. The Perrin Sequence are mentioned by Cephalon Cordylon in his 6th and 12th blog posts.