They said themselves that they seek competition. Originally, Harmony and Grind organised quite a few meetings before server launch because they wanted all competetive PvP guilds to play on Jordine so the server becomes very interesting and competetive.

Yet things kind of slowly developed into exactly the opposite direction with many of the best players from these competetive guilds all joining into Grind over time, who in turn recently merged into Harmony.

Both Grind and Harmony originally did not want to become huge guilds but rather focused PvP competetive guilds with max 100 players. (In earlier phases they even aimed for less than that!).... They wanted fun and balanced PvP fights and would often seek them out and sometimes even balance their forces according to the enemy strength so the fights would stay interesting.

A lot of their old principles were lost overtime, especially with much of the original leadership quitting, going to other servers or going back to KR. Nowadays it might be possible to take castles away from then, but not without pretty big alliances which I cannot see happening anytime soon.

The problem is not the other guilds being too small, just that the average Gearscore of Harmony is a lot higher than other big guilds.

I think a big factor in this development was the very late release of node and siegewars. At serverstart there was A LOT more potential competition who have disbanded ever since.