ETA: Oh, owlmoose is right. This should've been posted behind a cut. Hope I didn't spoil one of the early dramatic plot twists for anybody.
SO. Basch. Reks. King Graminas. Nalbina Fortress. WTF happened there? The first time we see it happen, we don't entirely know what's going on. Later in the game, we're given clues that help explain the opening sequence, but not entirely.
This is me trying to sort out who's who, where, when:
--Reks and Captain Basch get separated.
-- Basch and his men enter the throne room and are surrounded byImperials.
-- Basch's men are killed. He's captured and hauled off.
-- Reks enters the room and finds Basch's dead men, plus King Graminas, dead.
--A man in Basch's armor appears and stabs Reks. Reks says, "Captain, why?" thinking it's Basch.
-- Vayne enters, says, "Seize the insurgent!", addresses Mr. Stabbity as "Captain", and takes him to task for killing the king.
-- Mr. Stabbity says, "We'll never surrender to you! We are not cattle to be sold by a traitor-king!" and "We'll never bow to you!"
Mr. Stabbity has Gabranth's voice.
So, Mr. Stabbity has got to be Gabranth. But:
-- Why is he wearing Basch's armor, if he's been living in Archades and serving as a Judge Magister? Shouldn't he be in Judge's armor?
-- Why does Mr. Stabbity, a loyal citizen of Archades, say "we'll never bow to you!" as if he were an outraged Dalmascan protesting his King's surrender to Archades?
It appears that Vayne and Gabranth expected Basch to be there, and therefore planned in advance to have Gabranth wear his brother's armor and pretend to be Basch.
But why was it so important to frame Basch? I guess so it didn't look like the empire had killed Graminas?
Assuming this was all an elaborate masquerade to pin the blame on Basch, they needed a credible witness to be duped by this charade and report what he saw to the world.
So that's why they spared Reks.
Except...they didn't spare him! Gabranth stabbed him.
How did Reks manage to crawl from Nalbina Fortress back to Rabinastre to tell everybody, "Captain Basch killed the king...and ME!!!!"
It seems a bit paradoxical. Or at the least, it seems like poor planning to stage an elaborate hoax requiring a star witness, then mortally wound the witness and hope he tells someone before he expires.