If you rook a character (by killing it without blessings until level 6) and then switch to the new Monk vocation on Dawnport after its release, using the Death Redemption store blessing should work. The blessing is tied to your character, not the vocation, so it will not be blocked when you switch to the Monk vocation.
Keep in mind that each Death Redemption blessing will cost around 250 Tibia Coins (TC) each. As long as you purchase the blessing within the 24-hour deadline, it will be applied, and you can benefit from it after switching vocations.
Example Calculation for a Level 600 Character:
Levels to be rooked:
- From level 600 to level 6, you need to rook 594 levels (600 - 6 = 594).
Cost for 594 levels:
- 594 × 250 TC = 148,500 TC for the 594 levels.
Total Cost:
To rook a level 600 character (from level 6 onward), the total cost for Death Redemption blessings would be 148,500 TC.
This is based on a cost of 250 TC per level rooked.
However, I am not taking into account that at level 600, you might lose up to 2 levels per death. Additionally, you will recover a significant amount of skill that you previously had and convert it to the Monk version of that skill. Therefore, the best character to rook would likely be a mage, as the Monk vocation also uses magic, meaning you'll already have one skill improved.