Hoysepis stomped my decked STSF sword War Master Altariel with impunity more or less. I'm going to tell you how he did it.

Locate STSF (helps if you have air form). Attack using offence form. Is STSF packing more than 20% dam reduction (0% if they're decked and you have less than 1000 hp)? If yes, flee and do not fight them for 12 hours. If no, beat the crap out of them with rake/smash etc.

After 12 hours, locate STSF, repeat again.

You need: >1000 hp, and ABS.

Another concern: can STSF maledict? If yes, pack some +str/dex. Flee if str/dex gets nuked too badly and they're not almost dead with you at high hp.