If you want to get aden castle easy there is an interesting way that might have been patched on some servers and shared already but it still works on some servers (Like Dragon 15x in the D-N) All you need is a strider. This trick is a bit hard to pull off and sometimes even i can't do it form the first time...now then i will suppose you know how aden looks like. Go to the aden castle and go to the breakable wall on the left side so far so good? ok now get as close to it as possible use the arrow keys to bump into it then summon your strider and /mount it and again use the arrow keys and push on forward if you do it a few times you should be on the other side. Sometimes it gets bugged so that you see your charecter outside but its actually already inside if you think that is the case use the restart option from the linage 2 menu and relog the char. So far so good now find the breakable door that leads to the castle's inner hall
and do the same you did with the wall exploit inside with the strider..ok your in? Good :) now go up the stairs to the ramp entrance door its a small door that most people think is useless that lets you go on the ramp (the ramp is a biiiig long thingie above the plains of glory) strider exploit that door the same way you did with the wall and gate. When you pass through go doooooooown the ramp until you get something else than Aden Castle on the bottom of the map (alt+m and see bottom says Location:blablabla) or just run down to the first room-like thing on the ramp with a roof and log off there and voala when aden siege starts you are still there because the ramp is above a exp zone they can't make it a siege zone because people there will be able to battle and will be kicked out of the zone :).
Another way is to get some spy in the enemy clan to let you inside till you reach that ramp.
When you are there there are many options on what to do bit first you will have to break/exploit the small gate that you went through last to get to anywhere. Also getting a flag planted up there if your a clan leader during siege is really useful then your minions just die in siege zone press port to HQ and poof they are in some hidden spot near the top of aden where you placed the flag :) Ah also one last thing with some stealth you can get to the very top of aden castle and place your flag there no one will find it unless they know where to look :D gz inner invasion complete
Good luck to all :)
Ah i just saw this post here" http://www.maxcheaters.com/forum/index.php?topic=15841.0 basically exploiting with a strider is doing the same only without so many restarts but instead mount and dismounting the pet also this one is fixed on most server while using strider is less well known and patched on less servers