Feniurme
While I get where your coming from as it would be awesome to have a hero without falna, he’s going to need falna eventually to take on the horrors that the dungeon will create, and the more powerful criminals like the Dionysus and the Ishtar familias, as it was stated in the series so far that his max physical ability would be that of a veteran level 2 not saying he isnt powerful and skilled enough to take on D level 3s or people that got carried through the dungeon. He just will not be powerful enough to take on the many monsters he will encounter eventually as he goes deeper into the dungeon, and the actual pro adventurers that turned criminal. Not to mention it will be interesting to see what kinds of skills and abilities he will get from leveling up outside of his emiya abilities and to see how his emiya abilities potentially evolve because of the falna. Another thing is the possibility of him using the grimoire as I don’t know if you have to have falna to use it or not and the spell he could possibly get through it will be most likely pretty interesting.