You think he's gonna die in his fight? Who do you have him going up against?
I am kinda thinking here. Most of us expect the Gods to win this round 8. But what if humans win again? That would be the more unexpected outcome. Though it would probably make the rest of the fights more predictable.
I think Beel bites the dust in his fight, yes. Who's gonna do him in? Two possibilities:
1. Sakata, not only to close out the Buddha storyline connection, but also for one other reason: Sakata is known in his legend to love nature and animals, while Beel enjoys experimenting to the point where he consistently created eldritch abominations by corrupting/twisting nature or living beings. In this sense, Sakata and Beel foil each other, so this match-up requires very little explanation;
2. Simo Hayha. I know people have been hyping Simo vs Apollo for quite some time now, but aside from a possible new contestant for the Gods, there is a reason to believe why Simo might end up fighting Beel after all:
a. Apollo has a real-life connection to King Leonidas, because it was in the Temple of Apollo that Leonidas' fate to die in his famous last stand was revealed. Leonidas vs Apollo is also the last chance for the authors to give us a Greek Legend vs a Greek God;
b. Simo Hayha was a common man who became a hero by protecting his country against a giant evil before retiring as a successful dog breeder and generally living a modest life. Beel is himself a giant evil, maintained favors with the Chief Gods, desires to reduce humanity to ashes, and, like I said, consistently used nature for his eldritch-related curiosities. Even their appearance evoked comparisons ala Kojiro (an old man dressed like most ancient samurais) and Poseidon (a literal physical god dressed to show off his physiology): Simo wore a standard winter soldier uniform (and his face might retain its destruction), Beel is a beautiful-looking tall God dressed lavishly like a malefic priest.
Also, for the reason you have stated, I don't see humanity winning R8. The Gods have to win it to make R9 and R10 to be much less predictable.