With the series ended, i think it's time to put them in a pool. And a simple summarize good be nice, too.

But why is Norman Osborn Killing Yukkuris xD

A simple summarize? How about an easy translation? xD

He just do.
And I hope the ranger arrived to secure him soon.
Not for the yukkuri, the fire looks dangerous. Forest fire would be bad.

The can he had, that's spirits (the high alchohol kind). If he moved in his sleep and accidentally knocked it down and it reached the fire, it could have caused disaster.