The Nissin Di866 Professional can indeed work wirelessly with Canon products, but it cannot "see" the signals as readily as Canon Speedlites, in my experience, so it is best used as the Master flash. (In hindsight, I would rather have purchased a pre-owned 580EX for about the same price I paid for the Di866 Professional.) This is based upon using a 580EX and ST-E2 as Master units to control the Di866 Professional and Canon Speedlites. I have yet to try using the pop-up flash of a 7D as the Master flash.
In my experience, the lower portion of the remote/slave Nissin must be facing the Master Canon device fairly directly, whereas a remote Canon is less demanding in this regard. Of course, the presence of objects to reflect the signal would probably help a remote/slave Nissin to better receive the signal.
Another thing I noticed is that the Nissin behaved inconsistently at one location, when used as the only flashgun, mounted on my 40D. The scene had much confused ambient light from disparate sources, and was at night. I am not sure if this was a problem with the camera or the Nissin, or a perfect storm of events that might have caused problems, regardless, but the Nissin
has not misbehaved on either of my 7D cameras. (Notably, I was using a 24mm 2.8 lens that vignettes rather badly; let's keep in mind that in TTL modes, the flashgun is reading information gathered through the lens, and responds accordingly.)
I have not tried the strobing as shown by Jiko, so cannot address that question.
Canon 7D/5D/40D/1D2N; Nikon F6, D700, FM3A, & Coolpix A; Canon 40mm 2.8 STM, 135L, 50L, 35L, 50mm 1.8 I, 100mm 2.8L Macro, 10-22mm EF-S, 28-135 EF, 400mm 5.6L; Nikkor 50mm 1.2 AI-S, 50mm 1.4G, 50mm 1.8D, 16mm 2.8D Fisheye, 180mm 2.8D, 100-300mm 5.6 AI-S, 18mm 2.8D, Voigtlander 90mm f/3.5 SL II