http://www.ncsoft.com/en/legal/user-agreements/lineage-2-user-agreement.html
7. Official Service
NC Interactive has designed Lineage II for official play only as offered through the Service by NC Interactive at the Web Site and not through any other means. You further agree not to access, create or provide any other means through which Lineage II may be played by others, as through server emulators.
You agree not to use any hardware or software, including but not limited to third party tools, or any other method of support which may in any way influence or advantage your use of the Service which is not authorized by NC Interactive, including but not limited to the use of 'bots' and/or any other method by which the Service may be played automatically without human input.
You acknowledge that you do not have the right to create, publish, distribute, create derivative works from or use any software programs, utilities, applications, emulators or tools derived from or created for Lineage II, except that you may use the Software to the extent expressly permitted by this Agreement. You may not take any action which imposes an unreasonable or disproportionately large load on our infrastructure.
You may not sell or auction any Lineage II accounts, characters, items, currency or copyrighted material for real-world money or items or services of any value, nor may you assist others in doing so.
NC Interactive may from time to time in its sole discretion implement various forms of filtering, blocking or monitoring of IP addresses or proxies used to use, play or access the Game(s) or the Service, including without limitation blocking or filtering measures that restrict your ability to use, play or access Lineage II or Service outside of the territories in which NC Interactive makes Lineage II or Service available.