I have one of those - he's 22mo now but his temper scares even me - he's supposed to be the little one, but sometimes I feel so sorry for poor ds1, he is so patient with him and tries so hard not to retaliate. I heard him saying to ds2 the other day "NO! DON'T break up my train track! You KNOW it's naughty, STOP doing it! If you do it again, I will... I will.... POKE you!!" He didn't poke him of course, he came and got me, bless him. Ds2 goes out of his way to sabotage/steal/break everything ds1 is trying to play with. And yet he idolises him and wants to be with him all the time. They are really very close and protective of each other, but it surprises me that when there is a power struggle ds2 seems to have the edge.
I intervene and restate the rules of play, loudly so both boys can hear, remove the culprit temporarily from the situation and tell him quite clearly that it's not nice to snatch/whatever he's done, and that it makes his brother sad. He knows what I mean, and he's allowed back "in" when he's regained his temper. It does seem to be having an effect, I've noticed lately that when he's about to plough in and wreck something or push ds1 off something, he'll look around guiltily to see if I'm watching . I say "XXX..." in a warning tone, and it's usually enough. If not I usually swoop on him with some sort of distraction. If some way can be found for them to share, or for ds2 to have an nice easy task he can do to "help" ds1 with whatever he's doing (passing him bits of track, for example) it often stops the hostilities. I've no idea how "good" that is but it seems to work, for now.
I think some squabbling is inevitable, and it's surprising how it's often the littlest who has the fiery temper, and holds the older child to ransom because it's assumed the parent will blame the bigger child.