I see some folks misunderstand(?) Dan Heng's intentions with Blade. "I'll keep an eye on you" as in he will protect Blade, not fight him. "As you did for me," meaning he will continue to pursue him no matter Blade's protests (he has none lol). Dan Heng is *worried* for him. Blade reveals his script has something to do with "death." Yao Guang wants Blade destroyed. The IPC has a bounty on him. Blade has become the scapegoat of everything bad happening on Planarcadia.
The context of the entire conversation isn't as hostile as some are made to believe. Most of the conversation is amicably exchanging information sprinkled with some light teasing and banter. ("So what's your plan? Kill me again?")("Should I congratulate you?" "Much obliged.") As soon as Dan Heng gets shy, he flips it around and tries to look intimidating, which just makes Blade laugh. (Gosh they really still are Dan Feng and Yingxing).
Of course there was tension. "Oh my, things are getting heated." But it's not the same tension as the beginning of the game. They're not trying to kill each other anymore (and Dan Heng is not running from his past). Really "I'll keep an eye on you" is just a repeat/continuation of what Dan Heng said to Blade at Scalegorge "We have no choice but to continue the pursuit." "If you wish, I will see it through." Only this time it's not an obligation.
(Dan Heng is still not quite in the place to admit he *wants* to pursue Blade, hiding it under a veil of "I need to protect my friends," but we've seen what Dan Heng is like when he genuinely believes the Express crew is in danger and this is not it.)
And that's not even touching on the romantic implications of this scene (the hand holding, the near kiss, the camera angles, the abundant romantic tropes). Oh RenHeng the depth of your relationship is fascinating.
(Rewatching the scene, I didn't realise Dan Heng was FOLLOWING them, "skulking around." What a freak lmao no wonder Blade was teasing him).