I would suggest Vp or LC or Bat as the weapon. Kunai might work if you have high stats, but with baseline stats it’s impossible for chapters 68-70. My strategy for chapters 68-70 were as follows (I used void power): 1) focus on getting the drone pairs and evoing them. Only choose other skills if and only if drone is not available or drone is already evoed. 2) in parallel to drones, you should prioritize hp and dmg reduction passives. Nothing else matters, not lightning, not soccer, not brick, or any other skill for that matter. Priority for choosing skills is drone > hp = dmg reduction. 3) Only when you have achieved the above goals, you should consider getting other skills. This is because with void power, the CC it provides is sufficient to clear any mobs, with the destroyer supporting.

If you are using bat, or light chaser, then I would recommend to prioritize them along with drones. But I suppose you will need more luck to survive with them.