Hey there. The first character to complete the campaign should receive a questline called 'Destined Heroes', which is the exotic quest for Ergo Sum. The character that holds this quest, along with its subquests 'Lost in the Light' and 'Found in the Dark' will unlock a number of prismatic upgrades as they play these missions, and the missions will also become available for other characters, alt characters unlock the abilities from playing those, launching those from banner staves at the Tower. You know most of this I am sure, but one thing to say is, if the main character unlocks a mission but hasn't played it yet, alt characters can't earn the reward yet. I notice your Titan played Queens I in June, but your Warlock played Queens I, The Hollow I, The Hollow II, Home I and Home II in November so I believe your Warlock is the one with the Destined Heroes quest. However your Warlock has not played Queens II yet, and this I believe is what is locking the Hunter out of the reward for it, which is indeed the Strand melee. Could you check to see if the Warlock is the one with Destined Heroes. If their next step is Queens II, you'd need to play it on them first, and then replay it on the Hunter. That should unlock Threaded Spike for the Hunter.