So the sphere of stone is from J3 to I2 to J1 to K2? How much HP does stone actually have? Anyways, first things first:
Knowledge Devotion:
(1d20+28)[42]
Activate Boots of Speed, move out 40' forward to 10J and ready an action.
EDIT: 42 means +5 vs. all humanoids to attacks and damage for this encounter.
Readied Action:
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Readied action will be an attack on mage, condition being when he starts casting a spell.
Readied Maneuvers:
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Quicksilver Motion
Moment of Perfect Mind
Diamond Defense
Iron Heart Surge
Time Stands Still
White Raven Tactics
Mountain Hammer