more than 7 years playing maxko/titan , seen many things , many up and down , many events etc . For me , one of my best and hardest quest was khaless quest in old maxko . ahh it's was such a hard quest , start with farming dragon ball from servant of isiloon at hell abyss. Then give 20 dragon marbles to the clan leader and then he can enter with all the clan .
The party making also great . rouges with half archer and assassin skills ( 5 shot and 3 Shot arrow with 2 x Drain skills)
4 party will had 1 x bp in each party and 7 x rouges . warrior and mages were strictly forbidden by players , cause that quest is all about drain and arrow combo and duff

After we enter into jarod's cave , clan leader and his 3 x assistant used to make parties. Then we go for 1st room mob name Duras or something ( I don't remember , pardon me ) it drop 3 x key and it's respwan time was 45 min - 1 hour approx .
So we have to wait 1 hour for kill the next Duras for get 1 key for the 4th party . Every party leader should have 1 key to enter his party to 2nd room.
after 2nd duras killed , we got keys so we proceed to next rooms with 4 of our party , and again clan leader and his assistants have to make the party again .
This time for the mob names thoral , same rule , it's drops 3 x shord of thoral . respwan time also same as Duras 45 min - 1 hour .
after getting 4 shords of thoral , it has been distributed to the party leaders and we go for final room , the main house of jarod to get khaless .
This is the most hard part , cause jarod drop 3 x khaless and people really getting board after their party get the khaless . and minimum 3 party of full rouge need to kill it . It's was spawn faster like 5-10 min ...
Gm helps very often but without their help it was really enjoyable , it's made us to communicate each other , manage them to stay at the end , until all players get the khaless .
Well that's my experience about khaless quest and it is one of my favorite quest as well .