Chapter 165 of "Nanatsu no Taizai" or "The Seven Deadly Sins" is already available online courtesy of Manga Park. The current chapter continues the team battles where each team is composed of two warriors battling it out in separate stages. Before any predictions or spoilers on the upcoming chapters, here's a recap of the recent events.
The team of Ban and Melodias easily won their first match (without even knowing it) while Elizabeth and Elaine end up the victor in the battle against Tora and Jigmo. Each stage has their respective fight and Diane is partnered with King. The duo is facing Dolor Golem and Gloxinia Servant - representatives of Dolor and Gloxinia. The battle starts with Diane protecting King by placing the fairy on her bosom.
King complained that he also wants to fight and was eventually allowed by Diane. King showed his power by using 'spirit spear' to the surprise of Gloxinia and Dolor. King then revealed himself to Diane as someone special to her in the past. Gloxinia and Dolor decided to upgrade their representatives and Diane could not dodge the attack of Dolor Golem and was bound by Gloxinia Servant. Before the death blow to Diane's heart, she was saved by King. The chapter ends with King revealing his second form guardian Chastiefol.
The next chapter's title is "What Buds There" and user Kiriya from Manga Helpers speculates, "Next chapter's title definitely makes it sound like he's getting his wings - or that they're starting to grow, at least."
On the other hand, SirLemanz on Reddit forum on the latest chapter predicts something different for Diane so she could be a powerful warrior as part of Sins, "I'm just hoping that Diane gets like a power up arc or something like that quickly, right now I think she's like the weakest of the sins."
A powerful Chastiefol combined with Diane sounds like an interesting fight against Dolor Golem and Gloxinia Servant in the upcoming chapters.