The first thing to see with Sidar Kondo of Jamuraa is that he's brought Flanking back! Flanking is a powerful ability that reduces a blocking creature's power and toughness by 1 whenever it blocks a creature with Flanking. This is an ability that we haven't seen since Time Spiral. Being a 2/5 himself, this gives players a disincentive to blocking his attacks.
But the most important part of Sidar's ability is the fact that he makes all creatures your opponents control without reach or flying unable to block creatures of power 2 or less. What's interesting about the way this ability is worded is that it affects all of your opponents. So if an opponent is planning on swinging with a bunch of little creatures, they will be unable to be blocked as well, but you will still be able to block. What's even cuter about this ability is that after blockers are declared and no one is able to block, pump spells can be still used to buff your army during the combat damage step.
On his own, Sidar Kondo of Jamuraa looks to be a fun Commander to build around. But when partnering with the other Commander 2016 Legendary Creatures that also have Partner, there are many more options that present themselves. This guy is going to be a lot of fun.