I'm trying to start Act 3 but Malady is says to get everyone back on the ship first. Gareth is on the ship, but Tarquin isn't. I found him wandering around a in circles in the graveyard. I had already given him both pieces of Anathema, so when I talk to him the only dialogue I get is him talking about gathering a few odds and ends and then he can go back to the ship. I did some digging on forums and apparently that quest is all bugged to hell so I eventually gave up and killed him just so I could move on even though I really wanted to get that sword.

But wait, there's more! After I killed Tarquin I went to Malady to finally be able to move on to Act 3. But now she's telling me to fulfill my companion quests. I'm traveling wiht Fane, Sebille, and Ifan. Fane I'm not worried about because I definitely did his quest right without getting spoiler-y. And Sebille is definitely taken care of too because her quest log entry talks about going to the Nameless Isle. I'm pretty sure I'm screwed on Ifan's quest though because when I got into the fight with Roost, Sebille did all the talking and then the fight started. And then I read the note from Roost's corpse that's supposed to move the quest forward, and it logged in the journal, but when asked what we should do next Ifan says wwe should find Roost.

Is anyone having the same or similar problem and have a potential fix? I've put nearly 100 hours into this playthrough already (I'm very methodical with this kind of game) and don't have it in me to start over.

i might sound like an idiot but :
- did you try taking control of iban and reading the note
- do you play an origin or a custom made character
- did you sign almira up ? if so she may be referred to as a companion by malady

as a sidenote, i found that the sword isn't all that great, didn't even use it on the final combat (it was 2 lvls behind me maybe it's the reason) but went as broad sheild instead with the character that could use it.

- hell last chance, can you speak to his spirit with ifan ? maybe it does the trick

can't think of anything else.

Tarquin's quest line is bugged, this guy sometimes doesnt accept sword parts from blood island.
Gareth's quest can be bugged too, in my game i had completed his quests in Act 3, but he doesnt arrived on the ship. For some silly reason he's just appeared in the next act.
Dont know about others since they are sorta dissappeared from the ship after act 2 :/
Although Malady had asked me about missing Gareth, i had just ignored her and started the next act.Tarquin was moving between the ship and the cemetery, asking for the sword ;)
And many quests in Act 3 has been completed, but they was not marked as such in the Journal. Like the Red Prince quest line, like the cemetery watcher quest(did what was asked, quest hasn't marked itself as closed).