Sir Godfrey Gwilym

What we know

Named by bridge knight at Argynvostholt headquarters of Order of the Silver Dragon (Session 7 @ 02:31:53)
Party should seek him to oppose Strahd von Zarovich (Session 7 @ 02:31:53)
Knight said he is dead yet retains a name (Session 7 @ 02:46:14)
Tome of Strahd Ch. 2 vision: general at Argynvostholt gates during Strahd's siege; sister Alexandra Gwilym led the assault force (Session 25 @ 00:58:17)
Silvered longsword, holy fire fist (WIS save DC 15), and multiattack—overwhelming in vision combat (Session 25 @ 01:13:05)
Said "in another life we could have been allies" before being slain by Sildir's Divine Smite in the party's dream (Session 25 @ 01:27:07; Session 25 @ 01:44:40)
Sildir woke with Godfrey's silvered longsword bearing the Order symbol (Session 25 @ 01:47:01)

Fought in Tome of Strahd vision during Strahd's historical siege of Argynvostholt (Session 25 @ 01:04:33).

Bridge knights Tommy and Timmy directed party to seek him at Argynvostholt (Session 7 @ 02:31:53; Session 23 @ 01:37:41)
Vision combat: resisted Compelled Duel and Hold Person; frightened by Mercurio's Beguiling Magic (Session 25 @ 01:21:41)

Unconfirmed: whether any fragment of Godfrey survives at Argynvostholt today (Session 25 @ 02:06:52)
Unconfirmed: connection between the vision sword and Hoar's whisper to Sildir (Session 25 @ 02:05:18)