wise > {Sage; skilled in magic arts} whilom > formerly, of old wont > was accustomed they > (The chroniclers, e.g. Geoffrey of Monmouth in HRB 6.17)
6 To make his wone, low underneath the ground,
wone > abode, dwelling-place
7 In a deep delve, far from the view of day,
delve > pit, depression; ?cave (cf. 303.8:3, 207.0:1, 401.20:4)
8 That of no living wight he might be found,
That > [So that] of > by wight > person, creature
9 Whenso he counselled with his sprites encompassed round.
Whenso > Whenever counselled > deliberated; gave advice, took advice
303.8