It is impossible to bring to the fore the figure of the ‘mostrengo’ [monster] without evoking the ghostlike presence of Camöes's Adamastor which, although undeniably at work, seems to reduce Pessoa's poem ‘O Mostrengo’ [The Monster], from a critical perspective, to a mere answer, a reply, and echo of Adamastor. The aim of this essay is not to envisage the Pessoa poem through the prism of a ‘monster’ theme but rather to address the difficulty of naming otherness and of clearly delimiting ‘self’ and ‘other’. The indeterminate figure of the ‘monster’ in Pessoa's poem disseminates meanings, demonstrating how the structuring of language is always already at work in rendering indeterminate any or all essentialisms. Rather than a theme, its ‘monstrosity’ will be used as a point of entry into the puncturings of the images of empire, destiny, identity and other monolithic constructs, sustaining a promise of presence behind and beyond the text but which is ultimately structured, like language, at once referential and indeterminable. In attempting to address how the promise of a presence is enacted, and rather than falling back on what Jacques Derrida terms the ‘metaphysics of presence’, this analysis will look at how writing folds back upon itself while simultaneously dismantling meanings in a way that disrupts concepts of linearity, passage and identity.