Zaikhal Defenders

Difficulty:  Minimum to survive, Minimum to solo with melee D, max level range to solo without
Level Restriction:  50+
Timer:  1 Day for Helm, 2 Weeks for Coat
Can be Solo'd?  Yes
Rewards:  Invader Helm, Coat of the Zaikhal Defender

The Viamontians have struck!  Their vanguard arrived and surrounded Zaikhal, but it's not too late to save the town.  Dispatch the commanders of each invasion force and Zaikhal will be safe.

Step 1:  Preparation.  Head to Plateau Village first.  Mayoi's Oriel RQ portal is probably the fastest way.  Antius Blackmoor used to be stationed here to give you your assignment, but he's been replaced by a member of the Royal Guard.  You will be able to find him in the middle of town.  Greet him and he will give you a text detailing the invasion force.  Receiving this text flags you to enter the Viamontian portals, so it's a necessary step.  Now head to Zaikhal.  You might as well buff in town.  There are four different level ranges for this quest, meaning four different dungeons and four sets of enemies.  All the dungeons have a compliment of Eaters and Viamontians of appropriate levels, but some of the dungeons have additional enemies:

Step 2:  Legion Towers.  Each of the four dungeons have different layouts, but they are all relatively straightforward in design.  There is only one path that will get you to the end, although you may have to locate a lever or two to pass some doors.  Use [ and ] to find them!  Each dungeon has two main bosses - a Doorkeeper and a Captain.  The Doorkeeper holds a key to the door he guards - the only locked door in the complex, so kill him and grab it to continue on.  Shortly after the Doorkeeper is the Captain and his lackeys.  The Captain drops 5 Invader Helms and several  portal gems to Castle Corcima.  The quality of the helm depends on the level dungeon you visit.  Also note that the Captain's lackeys can also drop portal gems too, so grab a spare if you are concerned about your surviveability.  If you are feeling adventurous, you can find the Legion's Quartermaster too - he is in a spur section of the dungeon.  He guards several chests and carries a key to unlock two of them.  He is on a slow timer, so if you are taking a group, this really isn't such a good idea.  When everyone has their Helms, use the portal gem to summon a gateway to Castle Corcima.

Step 3:  Castle Corcima.  The castle is on an island between the Halaetans and northwest Osteth.  Each section's portal gems lead to a different region of the keep.  Regardless of where you appear, you will be facing a large number of Knights and Mages, as well as a Castellan and (at the 100+ range) General Corcima himself!  Both the Castellan and the General drop one vial of Royal Blood.  The General also drops several shards of his armor.  Everyone should grab a shard and then kill the two bosses until everyone has their vial of blood too.

Step 4:  Rewards.  You can immediately use the blood on the helm.  The 100+ Platinum Invader Helm gains Major Strength, Major Endurance, and Arcane Lore VII in addition to the base spells on the helm (Melee, Missile, Magic Ds and Impen VII).  Take the shard of armor back to Antius's replacement in Plateau and you will receive the Coat of the Zaikhal Defender.  Here are the Gold Invader and Blooded Gold Helm, as well as the normal and blooded Silver Helms.  When I have a chance to get images of the lower level rewards, I'll be sure to add them to the guide!