『Ruli, how's the jamming going?』


  『I have stopped their moves for now… I think! How about your side, Mathi-kun?』


  『I'm on floor 31 now, but there's no route going down. The demon probably made use of the Dragon Vein to change the internal structure to be that way. The skill level of the present humans can't reach floor 31.』


  I check the mana on the wall as I said that.

  …Judging from this state, the dungeon was probably tampered a few hours ago.

  I think they've done the preparation quite a while before that though.

  『Dungeon floor can't be broken right? Should I tinker with the Dragon Vein and create a path for you?』


  Destroying dungeon walls is simple, but doing so to the dungeon floor to move between floors is unexpectedly difficult.

  Because, even though the surface of the floor is soft enough that it sinks if Iris even steps on it, the floor gets harder after reaching a certain spot below the surface and going further beyond that is quite a task.

  The first floor is already harder than mithril.

  And it gets harder the deeper you go.

  At this floor… I don't think diamond can even scratch it——

  However.

  『No, I'll manage it myself this time. Ruli keep doing the interference.』


  True, there is a magic that can do that just as Ruli said.

  But I don't think the current Ruli can finish that fast enough.

  Even if she were to give up on interfering the demons and concentrate on the magic, it probably would still take three days to finish.

  …Therefore, I've got no choice but to break the floor.

  『Manage it yourself… Are you going to destroy the floor!? Isn't it impossible!?』


  『It's harder than breaking the walls sure but it's not impossible. We can break it with brute force if we have say, 10 times the power of Iris in her dragon form.』


  『Isn't that practically impossible then!?』


  Well, the current me can't put out 10 times the power of dragon Iris indeed.

  However, that much power is only needed if we intend to break the floor with brute force.

  『There's a trick to break dungeon floor you see. If you invoke a magic 200 times per second, the feat isn't really that far-fetched.』


  First, I activate 『Dig』 magic.

  This is a magic that simply digs the ground to make a hole like a drill.

  At first 『Dig』 magic continued to dig the dungeon floor nicely, but after a few meters down, it suddenly stopped and didn't move even a milimeter more.

  That means this is the true face of the dungeon floor.

  『200 times per second!?』


  I heard Alma's voice from the telepathy magic.

  『Yeah. There's this phenomenon called resonance. Like when an explosion happens, the grounds shake for a bit right? If you match the timing of that vibration with the magic, you can break things that are usually unbreakable.』


  『No well… Even if that was the case, even Mathi-kun can't possibly activate 200 magic in one second can you!? You're practically invoking all those magic at the same time!』


  True, the brute force approach would be faster than trying to invoke that many magic the regular way.

  However, there's actually a backdoor to invoke the same magic many times.

  『Mixing different magic with it is certainly not possible, however…』


  I activate pressure magic as I said that.

  Pressure magic will slightly shake the ground and disappear once it's done its job.

  I put additional mana into that pressure magic——and forcefully rebuild the magic——

  This is the backdoor trick. Magic Recycling.

  Of course, since this isn't how you usually use magic, it requires a very fine control of mana, but since you can invoke the magic simply by controlling mana in a very short amount of time, the magic activation rate has been raised by leaps and bounds.

  …That said, with crests other than the Disqualified Crest, like say the next speediest one, the Small Magic Crest can only output 130 times per second at most.

  The battle speeds between close quarter and ranged combat differ after all.

  Other Crests cannot activate magic at high speed.

  I raised the rate of mana supply while thinking about that.

  The vibration that shook the ground gradually got stronger——and after a few seconds, the dungeon floor collapsed.

  "…Well, guess this is just how it is on floor 31."

  I slip out of the mountain of debris while protecting myself from the collapse and touch a nearby wall to connect with Ruli.

  『Mathi-kun! The reaction on the Dragon Vein suddenly changed!』


  『Yeah. That's because I broke a floor. There are mana paths on the dungeon floors too, thus breaking them will affect the Dragon Vein.』


  I investigated the surrounding mana while saying that.

  …It's close.

  The demons are probably located two floor below here.

  『I'm close to the floor where the demons are. Prepare to interfere with the Dragon Vein here!』


  『I understand!』


  The sounds from the digging just now probably told our actions to the other party, it won't be strange if a battle breaks out anytime.

  Moreover, the fact that the demons could control Dragon Vein to block dungeon floor must mean that it's a reasonably powerful demon.

  Looks like I can expect a proper fight this time, sure been awhile.