Why do I feel that my inciting incident doesn't work?

I've layed out pretty much the whole story, yet going back to the beginning it made me feel it doesn't work and I don't understand why.

Here is my plot: an early medieval island has been destroyed by a mysterious necromancer that appeared out of nowhere. He commanded hordes of undeads, and both him and the dead could feel and locate the living. Everyone had been killed, and he's now roaming the land performing an endless spectral parade.

The MC is an undead warrior who is not under his control. Main flaw: he feels like he's a failed warrior and needs to avoid all confrontation. The other undeads attack him if they see him. He's kept alive by a glowing orb in his chest, and he's going around collecting other orbs, located over some altars spread out around the island. In his village lays his girlfriend and other villagers, in a magical coma. The MC goes around with a cat that can sense the orbs and guide him, and the MC can also hear the voice of his girlfriend if he touches him, like a distant whisper. She's the one who told him that he needs to gather the orbs to find the Moon Wizard, the only one who can stop the necromancer.

At first, the idea was that the inciting incident consisted in him going back to the village, when he thought the collection was almost complete, to find the orbs stolen. But then I felt like if there wasn't any foreshadowing on who the thief is, he wouldn't feel like a threat. But now that I added them, I feel like the inciting incident is weaker? Like, the fact that he's not the only one after the orbs doesn't sound like a breaking of the "regular world", where he is supposed to be alone, if there is some foreshadowing. And also, how do I show his flaw?

To fix the second part I've thought of beginning the story with a ship of merchants and some fighters landing on the island, just to be quickly killed by the undeads, while the MC was hiding nearby. This too break the feeling of post-apocayptic isolation though.

I don't know how to solve these two problems: foreshadowing of the first villain or not? How to show the MC flaw? There would be a ton of other stuff to say about this story, but I'll leave it at. In case it could be useful, I've come up with a way to have some flashbacks in the story, but I was thinking of them more as and explanation of the flaw and to show his past relationshios. I miss for a way to show it in the present. What am I doing wrong?