ततः thereafter, तत्र there, परमदारुणे exceedingly fearsome, तस्मिन् तमसि in that dark night, तेराक्षसाः those Rakshasas, सम्हृष्टाः highly delighted, शरवृष्टिभिः rain of arrows, राममेव Rama himself, अभ्यवर्तन्त assailed.

Thereafter in that exceedingly fearsome dark night in the battlefield highly delighted Rakshasas assailed Rama with a rain of arrows.