महाभारतः mahābhārataḥ - book-13, chapter-20, verse-16

अथोपविष्टयोस्तत्र मणिभद्रपुरोगमाः ।
निषेदुस्तत्र कौबेरा यक्षगन्धर्वराक्षसाः ॥१६॥

16. athopaviṣṭayostatra maṇibhadrapurogamāḥ ,
niṣedustatra kauberā yakṣagandharvarākṣasāḥ.

16. atha upaviṣṭayoḥ tatra maṇibhadrapurogamāḥ
niṣeduḥ tatra kauberāḥ yakṣagandharvarākṣasāḥ

16. atha tatra upaviṣṭayoḥ maṇibhadrapurogamāḥ
kauberāḥ yakṣagandharvarākṣasāḥ tatra niṣeduḥ

16. Then, as those two were seated there, the attendants of Kubera—namely, the Yakṣas, Gandharvas, and Rākṣasas, led by Maṇibhadra—also took their seats there.

Words meanings summery:

• अथ (atha) - then (then, now, thereupon)

• उपविष्टयोः (upaviṣṭayoḥ) - of those two (who were) seated (of the two seated, of the two who have sat down)

• तत्र (tatra) - there (referring to the place where the two were seated) (there, then)

• मणिभद्रपुरोगमाः (maṇibhadrapurogamāḥ) - led by Maṇibhadra (led by Maṇibhadra, having Maṇibhadra as their chief)

• निषेदुः (niṣeduḥ) - they sat down

• तत्र (tatra) - there (where the others were seated) (there, then)

• कौबेराः (kauberāḥ) - Kubera's attendants (belonging to Kubera, Kubera's attendants)

• यक्षगन्धर्वराक्षसाः (yakṣagandharvarākṣasāḥ) - Yakṣas, Gandharvas, and Rākṣasas (as categories of attendants) (Yakṣas, Gandharvas, and Rākṣasas)

Words meanings and morphology

अथ (atha) - then (then, now, thereupon)

(indeclinable)

उपविष्टयोः (upaviṣṭayoḥ) - of those two (who were) seated (of the two seated, of the two who have sat down)

(adjective)

Genitive, masculine, dual of upaviṣṭa

upaviṣṭa - seated, sat down, present, entered

Past Passive Participle

Derived from root viś with prefix upa

Prefix: upa

Root: viś (class 6)

Note: Used in a locative absolute construction, indicating the state of the two main characters.

तत्र (tatra) - there (referring to the place where the two were seated) (there, then)

(indeclinable)

Derived from pronominal stem 'tad' + suffix 'tra'.

मणिभद्रपुरोगमाः (maṇibhadrapurogamāḥ) - led by Maṇibhadra (led by Maṇibhadra, having Maṇibhadra as their chief)

(adjective)

Nominative, masculine, plural of maṇibhadrapurogama

maṇibhadrapurogama - led by Maṇibhadra, preceded by Maṇibhadra

Compound type : Bahuvrīhi (maṇibhadra+purogama)

• maṇibhadra – a proper name, a prominent Yakṣa
  proper noun (masculine)
• purogama – going before, leading, preceded by
  adjective (masculine)
  Prefix: puras
  Root: gam (class 1)

Note: Refers to the Yakṣas, Gandharvas, and Rākṣasas.

निषेदुः (niṣeduḥ) - they sat down

(verb)

3rd person , plural, active, imperfect (laṅ) of niṣad

Imperfect

3rd person plural, from root sad with prefix ni

Prefix: ni

Root: sad (class 1)

तत्र (tatra) - there (where the others were seated) (there, then)

(indeclinable)

Derived from pronominal stem 'tad' + suffix 'tra'.

कौबेराः (kauberāḥ) - Kubera's attendants (belonging to Kubera, Kubera's attendants)

(noun)

Nominative, masculine, plural of kaubera

kaubera - belonging to Kubera, relating to Kubera, a follower of Kubera

Vr̥ddhi derivative from Kubera

Note: Subject of 'niṣeduḥ', along with the following compound noun.

यक्षगन्धर्वराक्षसाः (yakṣagandharvarākṣasāḥ) - Yakṣas, Gandharvas, and Rākṣasas (as categories of attendants) (Yakṣas, Gandharvas, and Rākṣasas)

(noun)

Nominative, masculine, plural of yakṣagandharvarākṣasa

yakṣagandharvarākṣasa - Yakṣas, Gandharvas, and Rākṣasas (a collective term)

Compound type : Dvandva (yakṣa+gandharva+rākṣasa)

• yakṣa – a class of benevolent nature-spirits, often guardians of treasures
  noun (masculine)
• gandharva – celestial musicians and dancers, spirits of the air
  noun (masculine)
• rākṣasa – demonic beings, often hostile, but sometimes benevolent
  noun (masculine)

Note: Part of the compound subject, referring to the types of attendants.