Analysis of An Epitaph

Here lies one who never drew
Blood himself, yet many slew;
Gave the gun its aim, and figure
Made in field, yet ne'er pulled trigger.
Armed men have gladly made
Him their guide, and him obeyed;
At his signified desire,
Would advance, present, and fire.
Stout he was, and large of limb,
Scores have fled at sight of him;
And to all his fame he rose
Only following his nose.
Neptune was he called; not he
Who controls the boisterous sea.
But of happier command,
Neptune of the furrowed land;
And, your wonder vain to shorten,
Pointer to Sir John Throckmorton.