Asuras are easily more powerful due to their divine origin. They are naturally more powerful without plot armour like boons from gods .
Let's take demon vritra for example. He was so powerful that he was devouring the RTA cosmic waters of the universe . After killing vritrasur Indra restored the universe
- yad indrāhan prathamajām ahīnām
- ān māyinām aminā protā māyāḥ |
- āt sūryaṃ janayan dyām uṣāsaṃ
- tad īt nuṃ śatruṃ na kilā vivitse || 1.32.4 ||
- Literal
- “When, O Indra, you slew the firstborn of the serpents,
- you destroyed the magic/powers of the magicians.
- Then, generating Sun, Heaven and Dawn,
- you found no enemy indeed to withstand you.”
दि॒वो न तुभ्य॒मन्वि॑न्द्र स॒त्रासु॒र्यं॑ दे॒वेभि॑र्धायि॒ विश्व॑म् ।
अहि॒ं यद् वृ॒त्रम॒पो व॑व्रि॒वां॒सं हन्नृ॑जीषि॒न् विष्णु॑ना सचा॒नः ॥
It took the combined might of universe striding Vishnu and king of gods Indra to defeat him as explained in Rigveda
- uta mātā mahiṣam anv avenad amī tvā jahati putra devāḥ |
- athābravīd vṛtram indro haniṣyan sakhe viṣṇo vitaraṃ vi kramasva ||
- “And the mother looked upon the mighty one:
- ‘These gods are abandoning you, O son.’
- Then Indra, about to slay Vṛtra, said:
- ‘O friend Viṣṇu, stride out farther/wider.’”
विष्णुना सचानः
viṣṇunā sacānaḥ
“accompanied by Viṣṇu” — RV 6.20.2.
Similar example would be Madhu and kaitabha from ithihasas whose flesh was used to forge the planet Earth and mountains
- They were Madhu and Kaitabha and their bones covered everything and constituted mountains. The earth was formed from their fat
Rakshasas were human hybrids of ghandravas and humans . They are cannibals but nowhere possessed the power on the same cosmic scale as Asuras . Except Ravana and Kumbhakarna, who were descendants of saptarishis