When Link is still a child, Shikashi is seen wandering on the central place of Hyrule Castle Town. If he is spoken to, he will tell to Link the tale of the legendary Sheikah.
Link meet the Terminan counterpart of Shikashi (also named Shikashi) when he tries to obtain a Moon's Tear, in this game, Shikashi is a professor of astronomy who even owns his own Observatory, the Astral Observatory. He is one of the first to notice the unusual behavior of the Moon but only deduces that it will crash into Termina on the last day and realizes tht fleeing is futile as the moon will most likely destroy everything and not just Clock Town.
Ocarina of Time (Child)
After Impa's escape of Hyrule Castle Town with Princess Zelda, he will comment on the fact that Impa resemble to a Sheikah.
During Ganondorf's reign
During the 7 years reign of Ganondorf, Shikashi will flee to Kakariko Village. After Link's reawakening, he will tell him about the legend of the "Man who could see the truth" during the day and about the "Fabulously Rich Family" during the night.