In the premiere of Game of Thrones' eighth and final season, Cersei Lannister introduced a very thorny subplot into the mix. She bought the ever-buyable Bronn's loyalty with the promise of Riverrun and a real lordship, in exchange for taking out the only two friends he's ever made on this show. It was a weird subplot, and then for a while it didn't seem to go anywhere -- until the season's fourth episode, "The Last of the Starks."
While the two Lannister brothers were shooting the shit over some wine and "tall jokes" (Tyrion congratulating Jaime for having consummated his and Brienne's repressed relationship), who should saunter in but their former buddy, wielding a crossbow at the both of them. In that moment, most viewers were probably convinced that at least one Lannister was going to bite it, but then Bronn did something that we… honestly should have expected by now.
When Cersei and Qyburn made their deal with him, they promised him a castle, Riverrun, and a lady wife -- which are things that he both Tyrion and Jaime had promised him and failed to deliver, and Bronn said as much when initially refusing the offer. But then Cersei told him they'd also be willing to pay a literal wagon of gold up front, which swiftly changed Bronn's mind. Nothing like a classic half-now-half-later deal.
And that was pretty much as far as that went, until Bronn sidled up to Tyrion and Jaime and revealed the whole plan, at which point Tyrion reminds him of a promise he made early in their relationship, a promise to double whatever anyone paid Bronn to kill Tyrion. "What's double Riverrun?" Bronn asks rhetorically, but Tyrion, knowing exactly how to talk to a man like Bronn, immediately whipped out his trump card: Highgarden.
Highgarden, in case you don't remember, used to belong to House Tyrell, the richest house in Westeros. Their gold was the reason the Lannisters joined forces with them to end the War of Five Kings, cementing their power in the south and gaining a ton of riches along with it. Unfortunately for the Tyrells, Cersei blew up most of the remaining members in the Great Sept of Baelor when she was exacting revenge for her walk of shame. That meant Lady Olenna took over control of Highgarden until it was sacked by Lannister forces. After Lady Olenna's (badass, to be sure) death, the Lannisters are occupying the city and have either already transported or are planning to transport its gold to King's Landing. Riverrun, on the other hand, used to be the home of the Tullys annnnd doesn’t really have that much going for it, aside from sitting right at a very crucial point on the Trident river.
Bronn, of course, would go for the bigger prize in a second, but it's also a calculated maneuver. As he puts it, he's a gambling man, and right now the North still has two dragons on its side. He's seen them in combat, and he's not going to bet against them. After all, what good does Cersei's promises do him if she's burned to a crisp in King's Landing?
So he lets Tyrion and Jaime live (after firing a warning shot right next to Jaime's head), provided they make good on their word when this is all over. Is Bronn just going to stalk the sidelines, waiting for whoever is victorious to give him his due? Or will his benefactors -- either Cersei or Tyrion -- turn on him in the end, wiping another nefarious character from Westeros for good?
Obviously it remains to be seen, but Bronn's backchannel bribe-seeking has also given him a new rooting interest. He doesn't have to sit back and listen to Cersei just because she's paid him; he's now on the side of the Lannisters he actually likes, which means Bronn will be an unexpected ally to them when push comes to shove with Cersei. Maybe Bronn will prove to be the surprising key to the final battle for the Iron Throne.