Step 1: Concept
Absolute value inequalities.
Step 2: Analysis
For $x$ to be *always* negative, even the maximum possible value of $x$ must be less than 0.
From $|x - y| < 5 \implies y - 5 < x < y + 5$.
Step 3: Calculation
For $x < 0$ always, the upper bound $y + 5$ must be $\leq 0$.
$y \leq -5$.
The maximum integral value satisfying this is -5.
Step 4: Conclusion
The value is -5.
Final Answer: (D)