There are many earthly creatures who constantly represent the Rudra element. The snake, tiger and lion are always representations of Rudra. Sometimes, because of the extreme heat of the sun, there are cases of heatstroke, and due to the extreme coldness created by the moon there are cases of collapse. There are many sages empowered with the influence of austerity and many yogīs, philosophers and renouncers who sometimes exhibit their acquired power under the influence of the Rudra principle of anger and passion. The great yogī Durvāsā, under the influence of this Rudra principle, picked a quarrel with Mahārāja Ambarīṣa, and a brāhmaṇa boy exhibited the Rudra principle by cursing the great King Parīkṣit. When the Rudra principle is exhibited by persons who are not engaged in the devotional service of the Supreme Personality of Godhead, the angry person falls down from the peak of his improved position.
(Srimad Bhagavatam----3:12:11----purport).

Lord Brahmā said: My dear boy Rudra, you have eleven other names: Manyu, Manu, Mahinasa, Mahān, Śiva, Ṛtadhvaja, Ugraretā, Bhava, Kāla, Vāmadeva and Dhṛtavrata.
(Srimad Bhagavatam----3:12:12----translation).

Brahmā, as the father of Rudra, selected the wives of his son, his living places, and his names as well. It is natural that one should accept the wife selected by one's father, just as a son accepts the name given by the father or as he accepts the property offered by the father.
(Srimad Bhagavatam----3:12:14----purport).

The most powerful Rudra, whose bodily color was blue mixed with red, created many offspring exactly resembling him in features, strength and furious nature.
(Srimad Bhagavatam----3:12:15----translation).

The sons and grandsons generated by Rudra were unlimited in number, and when they assembled together they attempted to devour the entire universe. When Brahmā, the father of the living entities, saw this, he became afraid of the situation.
(Srimad Bhagavatam----3:12:16----translation).

Brahmā told Rudra: O best among the demigods, there is no need for you to generate living entities of this nature. They have begun to devastate everything on all sides with the fiery flames from their eyes, and they have even attacked me.
(Srimad Bhagavatam----3:12:17----translation).

Rudra was advised by Brahmā to perform penance as an example to his sons and followers that penance is necessary for attaining the favor of the Supreme Personality of Godhead. In Bhagavad-gītā it is said that the common mass of people follow the path shown by an authority. Thus Brahmā, disgusted with the Rudra generations and afraid of being devoured by the increase of population, asked Rudra to stop producing such an unwanted generation and take to penance for attaining the favor of the Supreme Lord. We find, therefore, in pictures, that Rudra is always sitting in meditation for the attainment of the favor of the Lord. Indirectly, the sons and followers of Rudra are advised to stop the business of annihilation, following the Rudra principle while the peaceful creation of Brahmā is going on.
(Srimad Bhagavatam----3:12:19----purport).

Śrī Maitreya said: Thus Rudra, having been ordered by Brahmā, circumambulated his father, the master of the Vedas. Addressing him with words of assent, he entered the forest to perform austere penances.
(Srimad Bhagavatam----3:12:20----translation).

The whole process of the creation, maintenance and dissolution of the cosmic manifestation is meant to give the conditioned souls a chance to go back home, back to Godhead. Brahmā created Rudra to help him in his creative endeavor, but from the very beginning Rudra began to devour the whole creation, and thus he had to be stopped from such devastating activities. Brahmā therefore created another set of good children, who were mostly in favor of worldly fruitive activities. He knew very well, however, that without devotional service to the Lord there is hardly any benefit for the conditioned souls, and therefore he at last created his worthy son Nārada, who is the supreme spiritual master of all transcendentalists.
(Srimad Bhagavatam----3:12:22----purport).

Lord Śiva, the king of the ghosts, sitting on the back of his bull carrier, travels at this time, accompanied by ghosts who follow him for their welfare.
(Srimad Bhagavatam----3:14:24----translation).

Lord Śiva, or Rudra, is the king of the ghosts. Ghostly characters worship Lord Śiva to be gradually guided toward a path of self-realization. Māyāvādī philosophers are mostly worshipers of Lord Śiva, and Śrīpāda Śaṅkarācārya is considered to be the incarnation of Lord Śiva for preaching godlessness to the Māyāvādī philosophers. Ghosts are bereft of a physical body because of their grievously sinful acts, such as suicide. The last resort of the ghostly characters in human society is to take shelter of suicide, either material or spiritual. Material suicide causes loss of the physical body, and spiritual suicide causes loss of the individual identity. Māyāvādī philosophers desire to lose their individuality and merge into the impersonal spiritual brahmajyoti existence. Lord Śiva, being very kind to the ghosts, sees that although they are condemned, they get physical bodies. He places them into the wombs of women who indulge in sexual intercourse regardless of the restrictions on time and circumstance. Kaśyapa wanted to impress this fact upon Diti so that she might wait for a while.
(Srimad Bhagavatam----3:14:24----purport).

Lord Śiva's body is reddish, and he is unstained, but he is covered with ashes. His hair is dusty from the whirlwind dust of the burning crematorium. He is the younger brother of your husband, and he sees with his three eyes.
(Srimad Bhagavatam----3:14:25----translation).

Lord Śiva is not an ordinary living entity, nor is he in the category of Viṣṇu, or the Supreme Personality of Godhead. He is far more powerful than any living entity up to the standard of Brahmā, yet he is not on an equal level with Viṣṇu. Since he is almost like Lord Viṣṇu, Śiva can see past, present and future. One of his eyes is like the sun, another is like the moon, and his third eye, which is between his eyebrows, is like fire. He can generate fire from his middle eye, and he is able to vanquish any powerful living entity, including Brahmā, yet he does not live pompously in a nice house, etc., nor does he possess any material properties, although he is master of the material world. He lives mostly in the crematorium, where dead bodies are burnt, and the whirlwind dust of the crematorium is his bodily dress. He is unstained by material contamination. Kaśyapa took him as his younger brother because the youngest sister of Diti (Kaśyapa's wife) was married to Lord Śiva. The husband of one's sister is considered one's brother. By that social relationship, Lord Śiva happened to be the younger brother of Kaśyapa. Kaśyapa warned his wife that because Lord Śiva would see their sex indulgence, the time was not appropriate. Diti might argue that they would enjoy sex life in a private place, but Kaśyapa reminded her that Lord Śiva has three eyes, called the sun, moon and fire, and one cannot escape his vigilance any more than one can escape Viṣṇu. Although seen by the police, a criminal is sometimes not immediately punished; the police wait for the proper time to apprehend him. The forbidden time for sexual intercourse would be noted by Lord Śiva, and Diti would meet with proper punishment by giving birth to a child of ghostly character or a godless impersonalist. Kaśyapa foresaw this, and thus he warned his wife Diti.
(Srimad Bhagavatam----3:14:25----purport).

Lord Śiva regards no one as his relative, yet there is no one who is not connected with him; he does not regard anyone as very favorable or abominable. We respectfully worship the remnants of his foodstuff, and we vow to accept what is rejected by him.
(Srimad Bhagavatam----3:14:26----translation).

Kaśyapa informed his wife that just because Lord Śiva happened to be his brother-in-law, that should not encourage her in her offense towards him. Kaśyapa warned her that actually Lord Śiva is not connected with anyone, nor is anyone his enemy. Since he is one of the three controllers of the universal affairs, he is equal to everyone. His greatness is incomparable because he is a great devotee of the Supreme Personality of Godhead. It is said that among all the devotees of the Personality of Godhead, Lord Śiva is the greatest. Thus the remnants of foodstuff left by him are accepted by other devotees as mahā-prasāda, or great spiritual foodstuff. The remnants of foodstuff offered to Lord Kṛṣṇa are called prasāda, but when the same prasāda is eaten by a great devotee like Lord Śiva, it is called mahā-prasāda. Lord Śiva is so great that he does not care for the material prosperity for which every one of us is so eager. Pārvatī, who is the powerful material nature personified, is under his full control as his wife, yet he does not use her even to build a residential house. He prefers to remain without shelter, and his great wife also agrees to live with him humbly. People in general worship goddess Durgā, the wife of Lord Śiva, for material prosperity, but LordŚiva engages her in his service without material desire. He simply advises his great wife that of all kinds of worship, the worship of Viṣṇu is the highest, and greater than that is the worship of a great devotee or anything in relation with Viṣṇu.
(Srimad Bhagavatam----3:14:26----translation).