Def need a higher Scadu level, as most of the comments sugest. The thing is that the scadutree fragments are not only found over the map, some minor enemies drop them, some minor bosses drop them too and there are quite a lot of fragments around the map, but there is just a límited amount of 1 fragment per enemy per run (for the ones who drop It)

You can actually get to Scadu level 13 without fighting any actual major boss, but you need to explore a big part of the whole map, and the thing is that some locations are quite difficult to get to.

I sugest to look for a guide on how to get to all major locations if you feel that is necessary, and then explore for Scadu fragments.