Surge
You take a deep breath and feel the magical energy flowing trough your body, enhancing your abilities. Starting at 2nd level, you can use your bonus action to expand spell slots to surge. When you do so you gain the benefit of one of following surges. The surge last for 10 minutes or until you enter a new surge. The different surges have different costs corresponding with the required spell slot level. You can expand higher level spell slots to combine effects of different surges. You can choose and combine surges with a total cost equal to or lower than the expanded spell slot.
1st level
Agile: Attacks of opportunity against you are made with disadvantage
Defensive: You gain a +1 bonus to your AC
Precise: You gain a +2 bonus to melee weapon attack rolls
Quick: Your movement is increased by 10 feet
Resilient Constitution saving throws are rolled with advantage
Sensing: You gain blindsight for a range of 10 feet
2nd level
Determined: You can not be charmed or frightened
Fast striking You can make two extra attacks if you use your bonus action for two weapon fighting
Silent: Your movement and attacks make no sound
Striking: Your weapon attacks deal 1d6 extra damage
3rd level
Evasive: You can take the Dodge action as a bonus action on your turn
Ferocious: When you use the Attack action, you can make an additional attack