Diablo – How does the Marauder’s new set bonus work with Kridershot

I can confirm that the life threshold is 10%. I have received this bonus a great many times, and have gotten it at 9.9%, but never more than 10%. You get the bonus when combat ends while you're below the life threshold. Combat is considered to end when you get a certain distance away from monsters, or when you're already at a distance from all monsters and kill something. This means that it's possible to get the bonus many times from a pack of monsters, by withdrawing at low health and then picking them off one at a time: You'll get the bonus for each monster you kill. I earned the Survivor achievement in less than an hour, in this way.

You damage numbers will be affected by the APS (attacks per second), enemy resistance, modified % on the skill (e.g. 300% for archon beam) etc.

Re. life on hit and life leech:

• Life on Hit of 65: LoH has hidden modifiers per skill; for most AoE skills you will get less than the stated value unless you actually hit a large number of targets
• Life Leech of 2.5%: This will be reduced per difficulty level; to a maximum of 80% in Inferno. At lvl 53 you are probably in Hell, so there is a 60% reduction. So your effective life leech is 2.5% * 40/100 = 1%

Galvanizing Ward passive ticks every 0.5 secs, so that 125 life means you are getting 250/sec (likely you have another 50 life regen from items, if Ward claims 200 regen)