Killer in the Dark

Today's Puzzle:

A smooth puzzle to finish the week with, ready for some difficult ones during the weekend!

It's many people's favorite with dog of war, and killer cages. Enjoy!

Link to Play Along:

Killer in the Dark by Flinty https://tinyurl.com/SudokuSleuthKillerInTheDark

Rules:

Normal Sudoku Rules Apply.

Fog of War - Most of the grid is covered in fog. As you solve more of the grid will appear.

Killer Cages - Digits in cages must sum to the number in the top-left corner, and digits cannot repeat within a cage.

All cages are exactly 3 cells in size.