Gather 6 of the Blooms from south and east of Karnor's Castle, near ( 173, 9, -62 ) /waypoint 173, 9, -62 (the flowers can be found south and east of the castle, between the pond and the little goblins). The flowers look just like the ones near the castle, but are clearly labeled Stonewood Jasper Blooms.
If you aren't interested in clearing all of Chelsith, there is an easy way to kill this mob without having to clear any trash. When you zone in move down the ramp and head off into the water on the left side, run up the small wall and follow the blue ledge all the way around to a point where you can hammer pull Mucus of the Deep One. Globs will hover over the ledge as part of the path they wander, but if you wait you can easily get by those, and there is one point where you get close to Yah-lei defenders, you can easily invis by these.
The last ingredients are two smoldering materials, which are semi-rare harvests obtained from any Tier 8 node (even fish). You must have a minimum harvesting skill of 340 for the relevant node type. You must harvest these materials; you cannot buy them or have them traded to you.
Once you have all four ingredients, return to Greater Faydark and turn them in to Orika Vikaarinen, the Royal Apothecary, upstairs and above the royal court ( 422, 143, 239 ) /waypoint 421.51, 142.95, 239.01.
Orika will send you a note in the mail that initiates the next step.
This quest is part of the Templar Epic Weapon Timeline, and can only be started/completed by a member of that class of at least Level 80.