This is Anti-kNight, Killer-X. 26(4) R28C28, 10(4) R37C37 and 26(4) R46C46 are disjoint cages.
Prelims
a) 13(2) cage at R2C3 = {49/58/67}, no 1,2,3
b) 14(2) cage at R2C7 = {59/68}
c) 14(2) cage at R3C1 = {59/68}
d) 16(2) cage at R7C2 = {79}
e) 12(2) cage at R7C8 = {39/48/57}, no 1,2,6
f) 19(3) cage at R1C5 = {289/379/469/478/568}, no 1
g) 26(4) disjoint cage at R28C28 = {2789/3689/4589/4679/5678}, no 1
h) 10(4) disjoint cage at R37C37 = {1234}
i) 26(4) disjoint cage at R46C46 = {2789/3689/4589/4679/5678}, no 1
Steps resulting from Prelims
1a. 16(2) cage at R7C2 = {79}, locked for N7
1b. 16(2) cage = {79} -> no 7,9 in R6C4 (AN)
1c. 10(4) disjoint cage at R37C37 = {1234}, CPE no 1,2,3,4 in R5C5 using diagonals
2. 45 rule on R5 3 innies R5C456 = 16
2a. 45 rule of C5 3 innies R456C5 = 12
2b. Total of 26(4) disjoint cage at R46C46 and two hidden 12(3) and 16(3) cages = 54 with R5C5 used for both hidden cages, i.e. one extra use -> R5C5 = 9, placed for both diagonals
2c. R5C5 = 9 -> no 9 in R37C46 + R46C37 (AN)
2d. R456C5 = 12 = {129} -> R46C5 = {12}, locked for C5 and N5
2e. Naked pair {12} in R46C5 -> no 1,2 in R5C37 (AN)
2f. R5C456 = 16 = {349} -> R5C46 = {34}, locked for R5 and N5
2g. Naked pair {34} in R5C46 -> no 3,4 in R37C5 (AN)
2h. 26(4) disjoint cage at R28C28 = {5678}
2i. Naked quad {5678} in R2C2 + R4C4 + R6C6 + R8C8, locked for D\
2j. Naked quad {5678} in R2C8 + R4C6 + R6C4 + R8C2, locked for D/
2k. 19(3) cage at R1C5 = {478/568}, no 3, 8 locked for C5 and N2
2l. 19(3) cage at R1C5 = {478/568}, no 8 in R2C37 (AN), clean-up: no 5 in R3C2, no 6 in R3C8
2m. 3 in C5 only in 14(3) cage at R7C5, locked for N8
2n. 3 in C5 only in R89C5 -> no 3 in R8C7 + R9C37 (AN), clean-up: no 9 in R7C8
3. 17(3) cage at R5C1 = {278} (only remaining combination), locked for R5 and N5, clean-up: no 6 in R3C1
3a. 17(3) cage at R5C1 = {278} -> no 7,8 in R37C2 (AN) -> 16(2) cage at R7C2 = [97], R5C3 = 8, clean-up: no 4,5,6 in R2C3, no 6 in R3C2, no 5 in R7C8
3b. 13(2) cage at R2C3 = [94], clean-up: no 5 in R3C8, no 5 in R4C1
3c. R3C2 = 4 -> no 4 in R2C4 (AN)
3d. R5C3 = 8 -> no 8 in R7C4 (AN)
3e. Naked pair {56} in R25C7, locked for C7, clean-up: no 7 in R7C8
3f. Naked pair {27} in R5C12 -> no 2 in R7C1 (AN)
3g. Naked triple {156} in 12(3) cage at R5C7, locked for N6
3h. 1 in R5 only in R5C89 -> no 1 in R37C9 (AN)
3i. 10(4) disjoint cage at R37C37 = {1234}, 4 locked for R7, clean-up: no 8 in R8C7
3j. 4 in R7 only in R7C37 -> no 4 in R8C5 (AN)
3k. 26(4) disjoint cage at R28C28 = {5678}, 7 locked for R2
3l. 9 in N2 only in R1C46, locked for R1
3m. 4 on D\ only in R7C7 + R9C9, locked for N9
3n. 4 in R7C7 + R9C9 -> no 4 in R6C9 + R9C6 (AN)
[I carelessly omitted the AN steps after placements for 16(2) cage at R7C2, which would have simplified things slightly. However it’s the same after step 4.]
4. 19(3) cage at R1C5 (step 2k) = {478} (cannot be {568} which clashes with R2C7, AN), locked for C5 and N2
4a. 4 in C5 only in R12C5 -> no 4 in R1C7 (AN)
4b. Naked triple {356} in 14(3) cage at R7C5, locked for N8
5. 7 on D/ only in R2C8 + R4C6, CPE no 7 in R4C8
5a. 7 on D/ only in R2C8 + R4C6 -> no 7 in R4C79 (AN)
5b. 7 in N6 only in R6C789, locked for R6
6. R5C1 = 7 (hidden single in C1)
6a. R5C2 = 2 -> no 2 in R37C3 (AN)
6b. 10(4) disjoint cage at R37C37 = {1234}, 2 locked for C7
7. R3C37 + R4C5 form naked triple triangle (because of AN) = {123}, 3 locked for R3 and 10(4) disjoint cage at R37C37
7a. 2 in R3C7 + R4C5 -> no 2 in R4C9 (AN)
7b. R37C3 + R5C4 form naked triple triangle (because of AN) = {134}, 1 locked for C3 and 10(4) disjoint cage at R37C37
7c. 3 in R3C3 + R5C4 -> no 3 in R1C4 (AN)
7d. 4 in R5C4 + R7C3 -> no 4 in R9C4 (AN)
7e. R37C7 + R5C6 form naked triple triangle (because of AN) = {234} -> no 3 in R1C6, no 4 in R9C6 (AN)
7f. R6C5 + R7C37 form naked triple triangle (because of AN) = {124} -> no 1 in R6C1, no 2 in R6C9 (AN)
7g. 3 in N2 only in R2C46, locked for R2
7h. 1 in N4 only in R46C2, locked for C2
7i. 2 in N6 only in R46C8, locked for C8
7j. 4 in N8 only in R8C46, locked for R8
8. 12(2) cage at R7C8 = [39]
8a. R8C7 = 9 -> no 9 in R6C8 (AN)
8b. 3 on D\ only in R1C1 + R3C3, locked for N1
9. 4 in C1 only in R69C1 -> no 4 in R7C3 (AN)
9a. R7C3 = 1, placed for D/, R3C3 = 3, R3C7 = 2, placed for D/, R7C3 = 4
9b. R3C3 = 3 -> no 3 in R5C4 (AN)
9c. R3C7 = 2 -> no 2 in R1C6 + R4C5 (AN)
9d. R7C3 = 1 -> no 1 in R6C5 + R9C4 (AN)
9e. R7C7 = 4 -> no 4 in R5C6 + R6C9 (AN)
9f. R46C5 = [12] -> no 1 in R2C46, no 2 in R8C46 (AN)
9g. R5C46 = [43], R2C4 = 3 (hidden single in C4), R8C6 = 4 (hidden single in C6)
9h. R4C8 = 2 (hidden single in R4), R6C2 = 1 (hidden single in R6)
9i. R7C3 = 1 -> no 1 in R9C4 (AN)
9j. 1 in R3 only in R3C46, locked for N2
10. R3C8 = 9 (hidden single in C8) -> R2C7 = 5
10a. R2C7 = 5 -> no 5 in R4C6 (AN)
10b. R5C7 = 6 -> no 6 in R3C6 (AN)
10c. Naked pair {15} in R5C89 -> no 5 in R7C9 (AN)
10d. 26(4) disjoint cage at R28C28 = {5678}, 5 locked for R8
10e. 5 in N9 only in R89C8, locked for C8 -> R5C89 = [15]
10f. 5 in R4 only in R4C234 -> no 5 in R6C3 (AN)
[Looks like I need to try forcing chains now.]
11. Consider placement for 2 on D\
R1C1 = 2
or R9C9 = 2 => R8C1 = 2 (hidden single in N7)
-> no 2 in R2C1
11a. R2C6 = 2 (hidden single in R2)
12. Consider placement for 4 in R4
R4C3 = 4 => R9C1 = 4 (hidden single in C1), placed for D/
or R4C9 = 4
-> no 4 in R1C9
12a. R1C9 = 3, placed for D/, R9C1 = 4
13. Consider permutations for R34C1 = [59/86]
R34C1 = [59] => R3C6 = 1, R3C4 = 6 => no 6 in R2C2 (AN)
or R34C1 = [86] => no 6 in R2C2 (AN)
-> no 6 in R2C2 (AN)
13a. Variable hidden killer pair 5,6 in R1C23 and R23C1 for N1, R1C23 cannot be {56} which clashes with R1C46 = {569} -> R23C1 must contain at least one of 5,6 -> R34C1 = [59] (cannot be [86] because R234C1 = [186] doesn’t contain either of 5,6)
13b. R3C1 = 5 -> no 5 in R4C3 (AN)
13c. Naked pair {46} in R46C3, locked for C3 and N4 -> R19C3 = [25], R6C1 = 3, R1C1 = 1, placed for D\
13d. Naked pair {68} in R7C1 + R8C2, locked for N7
13e. Naked pair {68} in R7C1 + R8C2 -> no 6 in R6C3 (AN)
13f. R6C4 = 5 (hidden single on D/)
13g. R46C3 = [64]
13g. Naked pair {78} in R6C78, locked for R6 and N6
14. R2C59 = [41] (hidden pair in R2)
14a. Naked pair {78} in R1C57, locked for R1, R1C2 = 6, R8C2 = 8, placed for D/
and the rest is naked singles, without using anti-knight or diagonals.