In Pyramid #3/60: Dungeon Fantasy III, Antoni Ten Monrós wrote “Mystic Power-Ups”. One of the neat things he did there was create “imbued soul” power-ups. For one of my games I expanded this for a PC and this is what he was using:
12, 32, 41, 68, 128 points
Levels 1 and 2 function per the article, but “Resistant to Electric Shock” has been renamed to “Resistant to Electrical Effects” for the same cost. At level 3, DR vs. lightning effects (maladictive or otherwise) increases to 5 and resisting electrical conduction gains a +3 to rolls. At level 4, DR becomes 10 and resisting electrical conduction or noxious effects gains a +8 to rolls. Additionally, the knight can use Fulminating Strike, Electric Weapon, and Insulating Armor on the DR or innate attack bonus gained from having Lightning Imbued Soul. At level 5, DR becomes 20 and the knight is immune to electrical conduction and electrical noxious effects.
Statistics: Level 1 and 2 are per the Pyramid article. Level 3 increases Damage Resistance to 5 (for 4 points) and adds Internal Damage Resistance 5 (Limited, Electricity, 40%; Magical, 10%)  + Resistant to Electrical Conduction (+3) (Force Field, +20%; Magical, 10%) . Level 4 increases DR to 10 (for 17 points), Internal DR (for 2 points), Resistant to Electrical Conduction to (+8) (for 2 point), and Resistant to Noxious Electrical Effects to (+8) (for 5 points). It adds Rules Exemption (Fulminating Strike, Electric Weapon, and Insulating Armor can be used on traits from this ability) . Level 5 increases Burning Attack to 2d (for 12 points), Damage Resistance to 20 (for 35 points) and increases Internal Damage Resistance 10 (Limited, Electricity, 40%; Magical, 10%) (for 5 points). It swaps Resistance to Electrical Conduction for Immunity to Electrical Conduction (for 2 point) and Resistance to Noxious Electrical Effects for Immunity to Noxious Electrical Effects (Force Field, +20%; Magical, 10%) (for 6 points).