Logic Masters Deutschland e.V.

The following puzzle is a big puzzle consisting of 4 small sudokus linked together by extra conditions, and this is the 6x6s version of my previous 4x4s puzzle, which can be found in this link. This one actually took me quite longer than scheduled since I did want to share this one as the New Year gift but there were some troubles related to the later half of the setting so I had to delay a bit and fix some things that I was missing.

As said before, the rule set is pretty much as long as the 4x4s one but given how widely familiar most of them are, I think it shouldn't be so daunting overall but careful reading is still required ultimately, especially at the end. I hope you enjoy!

Rules:

- Normal Sudoku rules apply for each of 6x6 grid, each contains a set of 6 digits from the set of digits from 1-9 and solver needs to deduce which digits each grid has to contain.

- Variant applies for each grid:
+ Killer: Digits within a cage don't repeat and they sum to the small number written in the corner of that cage (the 2x2 cage means that the total of that cage is smaller than 22).
+ Double arrow: For each gray line connected by two circles, the sum of digits in those two circles is equal to the sum of digit[s] along that gray line.
+ Mathrax: Each circle contains a number and an arithmetic operator, where the number is the result when you apply that operation to both pairs of diagonally opposite cells (in this case, x is multiplication and / is division). Each ? is a number that needs to be deduced (not necessary an integer).
+ Factor sum: For each cell with an arrow in it, the sum of the FIRST TWO CELLS along the arrow's direction from that cell is equal to a FACTOR of the value in that cell. For example, if R2C1 is 6 then the sum R3C1+R4C1 is either 1,2,3 or 6.

- A square between two adjacent grids contains a thing that shows some relationships, including:
+ Two adjacent cells contain digits with consecutive relationship - indicated as a white dot.
+ Two adjacent cells contain digits with the total of 5 - indicated as label V.
+ Two adjacent cells contain digits with the total of 10 - indicated as label X.
+ The sums of the first two cells from each side are equal - indicated as label =.

- A given hyphen (-) in the square shows that none of above relationships are valid in that square. If a hyphen isn't given in a square, the square must be either one of the four above relationships.

- In a series of six consecutive squares, besides two hyphens, no two of them will contain the same label, e.g. if one square contains a V, none of the rest in its series can contain another V.
MOREOVER, NEGATIVE CONSTRAINT APPLIES FOR ONLY '=' RELATIONSHIP: if the sums of the first two cells from each side of a square are equal, that square MUST be labeled as '=' and no other square in its series will follow same such relationship.

Puzzle (no answer check): Penpa plus link

Good luck and have fun solving!