Hi!
Best Protection to wear: Fire and Physical Protection (even on its freezing form, the boss deals fire damage)
The best way to Trap the Boss would be the following:
It really doesn't matter where your trap is as long as the EK and RP are the only ones getting damage from the boss. It is extremely important the EK uses a lot of "exeta res" since it retargets a lot, especially when it changes its form.
About the boss and the killing strategy:
| The Time Guardian: When its top is gray, the boss is only weak against physical damage. EK & RP should use their strongest weapons and mages should use Explosion Runes. |
| The Freezing Time Guardian: When its top is blue, the boss is weak to fire damage. RP could change use Flaming Arrows + Great Fireball Rune (GFB) and mages only the GFB (Great Fire Wave and Strong Flame Strike are also a good option for sorcerers). If you deal enough damage in this form, Lost Time will spawn, kill it and use the corpse in the Time Waster (those are immune to all damage and the only way to get rid of them is by using the Lost Time corpses). |
| The Blazing Time Guardian: When its top is red, the boss is weak to ice damage. RP could use Shiver Arrows + Avalanche Rune and mages only avalanches (and Strong Ice Wave and Strong Ice Strike for druids). Depending on the amount of damage he takes in this form, he will summon Time Wasters. |
Note: In my personal experience, the blazing form is the one that if you deal a lot of damage will spawn lots of time waster, so I would focus more on keeping a healthy balance of fire and ice damage.