Yeah, like Night said, using BB while its knocked-down completes the combo. It has a pretty small window too, I generally use BB right as the target is falling down, the moment he is getting back up the combo doesn't seem to finish anymore.
Thanks! And yes, I agree. My build is slightly different from this, mainly because I plan to solo a lot and this build is most effective in group play.
I think it actually works using the knockdown of others, will test more and reconfirm
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