Hi, Nejira,
Shar bu is the High Lord of
all of the I-Lat Norg.
A
Lat comprises five lesser Shards led by a Greater Shard. Which is the basically encountered 'group'. (I've had a group of Shards terrorising my players- and even had them at the point that they'd go on the defensive if they heard the tree's rustling for no apparent reason.)
A group of 'related' Shards form an
I-Lat and there are a total of six I-Lats, Dir, Samli, Viour, Thanor, Ubenmas and Aarn Voru, and each I-Lat has a single Lord- one of the
I-Lat Norg; Shar-Ti, Quorn-Tas, Shar-Lac, Orlak-Shar, N'Koru and Leste Kii Lormas respectively.
Shar Bu stands above the I-Lat Norg- essentially he's the ultimate Shard. My players might have been able to handle one of the the I'Lat Norg- if they hadn't been too busy gibbering and panicking whenever I mentioned 'rustling sounds in the trees'.
Shar Bu on the other hand would have wiped the floor with them, in a couple of rounds.
The information's in the Master Atlases.
Hope this helps.
All the Best,
Kevin.