At Loggerheads (Jack of Spades)

This is a fairly tough word/logic puzzle combination.

Hints & Solutions
Highlight the white text inside the block for hints ranging from vague to specific...

Hint 1: Start by solving the clues using only the letters found in HYDRAE. Hint 2: The starting letters for each clue are:

Titaness mother of the Olympian deities: R

Daughter and anagram of that titaness: H

One of the 20 Odysseus spent wandering: Y

Measurement of threee feet: Y

Prepared: R

Tough and resilient: H

Feeling of eerie discontent: D

Parent, familiarly: D

Paid attention to: H

Bleak and ominous: D

One with a flock: H

Time of greatest accomplishment: H

One called "Firehair," perhaps: R

Calculated a new sum: R

Attached with glue: A

What there might not be in the house when sad songs play: A Hint 3: Transfer the letters ABOVE the numbers in the clue answers to the grid. Double-check this 3 times, because it is super-easy to switch to adding the letters below the numbers to the grid instead. Hint 4: The directions are a little ambiguous, so to clarify: all of the letters in one instance of the word "HYDRA" are part of one head. No letter from one head is orthogonally adjacent to any other letter from another head. They are diagonally adjacent, however. Also, when it says "Each of the squares in the grid will contain a letter when you're done" what they are saying is fill in a letter E whenever a cell cannot contain a letter from a head due to a head "looking" in that direction. Personally, I find it easier to fill a cell with a dot so that the letters for the word HYDRA pop out cleaner. Hint 5: The middle two rows of the grid are as follows:

EARDEHEEEEAYH

EEEEDYEEEERDE Hint 6: The next section contains the answer. Do not reveal unless you want to be spoiled The Solution:

Row 1: EAE

Row 2: RDERDYH

Row 3: EEEEAYE[]EEEEHYA

Row 4: AEARDEHEARERAEDRE

Row 5: EREEEYH[]EYDEDE[]EEHE

Row 6: EDEAREEEEH[]HYEARDYE

Row 7 EYH[]DEEEEEEEEEEEEEE

Row 8: EEHYEEEEEEARDYHEE

Row 9: E[]EEYHEEEEEEEEE

Row 10: EARDEHEEEEAYH

Row 11: EEEEDYEEEERDE

Row 12: RAEAEREEEYHEE[]E

Row 13: YDEEREAEEEDEEDYHE

Row 14: EHEAEDEEEEERAER[]EAR

Row 15: EEDREYHE[]EHEEEAEEED

Row 16: EEYE[]EEHYEY[]EEEEEHY

Row 17: EHEEEEEDEDRAEERAE

Row 18: EARDYER[]EEEHYDE

Row 19: HEAEDRA

Row 20: EHY

The keyword in the shaded letters is "DRYAD"