Raika

Straight from the snow-covered lands up north, Lieutenant Raika (Laika in Japan) of Sharo’s Net Saviors joins up with Lan and Chaud in a fight against Dr. Regal and the Darkloids.

MegaMan Battle Network 4
Raika first shows up in the final rounds of the Red Sun Tournament. He spied on Lan and came before him to say that he was weak and would be defeated easily. Lan grows enraged and attempts to punch him but Raika easily brushes him off. Then after Lan defeats Nebula Navis in the Undernet, Raika declares that after watching him battle, there was a 99% chance of victory. However, he is still defeated by Lan and returns to Sharo after revealing that the reason he came was to demonstrate Sharo's millitary power, which he failed to accomplish.

MegaMan Battle Network 5
Raika joins Team ProtoMan.

MegaMan NT Warrior
Using a combination of quick thinking and his tactical NetNavi, SearchMan, few have ever come close to beating them. Disgusted by the fact that Japan’s Net Saviors rely on Synchro Chips and Cross Fusion to defeat their enemies, he continually insults Lan's and MegaMan's intelligence and inability to analyze battle situations.

The past is forgotten(although not by much), however, when Laika returns in Rockman EXE Stream with a new SyncroChip (and a better attitude), completing the Cross Fusion trio and adding a new member to the chosen marked with the Crest of Duo(this is rather ironic, as the Axess Raika would have never even thought or relied on Cross Fusing).

Laika bids his comrades goodbye and returns to Sharo early on in Rockman EXE Beast, but returns a few episodes later.