Dens Devilish Level 261

Rows count from the top, columns from the left. Each line says where the next monster goes and why.

1. row 6, column 1. The orange den has only one free spot left. Its monster moves in there.
2. row 8, column 2. Row 7: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. The pink den: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. The yellow den: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. Try a monster on the marked spot and follow it through: the blue den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: column 5 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: column 5 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: column 5 ends up without a spot. So no monster goes there. Row 10: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. Try a monster on the marked spot and follow it through: row 8 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 8 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the mint den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 8 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the yellow den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 10 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: column 3 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the blue den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the yellow den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: column 5 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 5 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 7 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 7 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 5 ends up without a spot. So no monster goes there. Row 7: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. Row 8: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. Try a monster on the marked spot and follow it through: column 2 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: column 3 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the pink den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the lilac den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the mint den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 9 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the pink den ends up without a spot. So no monster goes there. Row 7: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. Try a monster on the marked spot and follow it through: the blue den ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 9 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 9 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: the purple den ends up without a spot. So no monster goes there. Row 7 has free spots in one den only: the green den. Its monster must go into this line, so the rest of the den is out. Try a monster on the marked spot and follow it through: row 1 ends up without a spot. So no monster goes there. The pink den: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. The pink den and the blue den fit only into rows 1 and 2. Together they fill these lines, so every other spot there is out. The yellow den fits only into column 5. Whichever spot its monster takes, that line is used: cross out the rest of it. Columns 2, 3 and 4 only have spots in the green den, the red den and the turquoise den. Their monsters take all of them, so the other spots there are out. Row 8 has free spots in one den only: the red den. Its monster must go into this line, so the rest of the den is out. Row 9 has free spots in one den only: the lilac den. Its monster must go into this line, so the rest of the den is out. Row 7: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. The red den has only one free spot left. Its monster moves in there.
3. row 7, column 4. The green den has only one free spot left. Its monster moves in there.
4. row 10, column 3. The turquoise den has only one free spot left. Its monster moves in there.
5. row 1, column 6. Try a monster on the marked spot and follow it through: column 6 ends up without a spot. So no monster goes there. Try a monster on the marked spot and follow it through: row 1 ends up without a spot. So no monster goes there. The purple den fits only into row 5. Whichever spot its monster takes, that line is used: cross out the rest of it. Row 4: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. Column 6 has only one free spot left, so a monster goes there.
6. row 2, column 9. The blue den has only one free spot left. Its monster moves in there.
7. row 3, column 5. Row 3 has only one free spot left, so a monster goes there.
8. row 5, column 10. Row 4: a monster on a marked spot would see or touch all of its free spots. Nothing would be left there, so cross the marked spots out. The purple den has only one free spot left. Its monster moves in there.
9. row 9, column 7. The lilac den has only one free spot left. Its monster moves in there.
10. row 4, column 8. The mint den has only one free spot left. Its monster moves in there.