Not quite sure why the MC's fight is even lasting this long (just for tension, I suppose?) considering the level gap and even class disparity (to some extent). A lvl 99 +5 (lvl 104) vs. a level 59 should realistically be over in a matter of seconds. I guess he's toying with him to vent some anger? Still, seems rather reckless considering there are two more similar combatants fighting your other companion's.
My guess on how things will unfold: Fighting will continue. Priestess chick will show up and recognize Ruri. She will mention some skill she has that might save him, but she's unsure because she's never used it on a monster. Tension increases. Priestess spell works. Fighting will continue for a bit until Chappi reappears or is noticed by the MC. From there the S class will mention how they are at a disadvantage and retreat while vowing retribution . Monsters want to give chase and MC tells them not to. Everyone celebrates while swearing to get stronger. MC will decide his presence is a threat to the village and choose to leave. Priestess decides to join him since she'll be reported for 'helping monsters". Not sure if elf chick will choose to stay or join. They then leave while ordering all remaining local monsters to protect elf land. Meanwhile, the S Ranks will report the situation to the King or guild who will automatically assume the MC is the Demon Lord since they have no records of anyone as strong as him with a taming class.
That's about what I anticipate. It seems kind of by-the-numbers and I'm sure most will be wrong, but we'll see. Im hoping at least one or two of the S Ranks die, but I just can't see it happening.