From this drawing, I saw someone filled with grief and pain. I went to your series to read the summary and to see the main genres.
My suggestion after reading your summary is to add your OC with a tree on the side and some grave stones. It will add mystery plus show the pain of your OC.
You can go with many designs. You can show your MC clenching their fist in grief. You can show their back while facing the graves of their family near the tree. You could go with the current pose/expression but a bit far away to show the rest of the scene.
I feel like there's a lot you can do to show the grief and pain while keeping the mystery. Another option is to add a tree and instead of adding gravestones you can add something that represents that the OC's family died. It can be a picture with black ribbons, a cross (pseudo improvised grave), or your OC can place a flower with some stones representing a grave.
You can place your OC in a house with a picture of his family broken in the background plus a tree that can be seen through the window. You can add your MC watching a toy that his kid (if he had one) used with a flower on top, under the tree. Or something that represents his wife or whoever died. Usually, children pseudo graves get represented with their toys/plushies.
The ideas keep flowing with many things you can do with your cover.
You can even add a dead demon recently killed by MC in the background but make it subtle. Make it a small detail. Let it be something a viewer sees next after seeing the tragic scene of the OC's pain and after seeing the tittle/logo.
Your summary told me a lot about the plot and main genres. Try to show it with your cover. I do not know if the parents of your OC died or if the family was destroyed in a metaphorical way. (Read the few chapters but you haven't said anything of what happened yet.) Dead demons or demon skulls can show some action but if you do add them make it be the third thing people see in your cover. First the pain, then the tree, and finally the demons.
P.S. Hope this helps bring you ideas to your head. After all, you are the author and the only one who knows how the MC is in pain and how his family got destroyed.
P.S.S. In any cover we won't be able to know the whole story but it is important to show the reader the most important details. Think of it like a visual summary. This new drawing is a huge improvement by showing me the MC was in pain. You are only missing to add a way to convey to the viewer how he is in pain. I think graves or pseudo graves work perfectly for this (assuming people died). I do think a tree should be added since it represents the tittle/the family tree but that is your decision as the author. (I can see the leaves but a tree feels just right considering the tittle.)
